I've researched that a lot myself.  I don't have specific experience with it to draw from so my opinion is based only on what others have posted, whether for a S40/Savage or other bike.  My feeling is that it's better suited for an occasional, weekend perfect weather rider bike and not so good for a daily commuter or high mileage rider.  I've read about issues with the left side upper strut mount cracking due to the pressures placed on it when hitting a big bump.  This, I've also read, can be resolved by welding additional support in the area between the left upper mount and frame.  But this requires properly repainting the new welded support if you want it to look decent.  Descriptions of the rear getting airborn after hitting a bump worries me too.  On a turn this could be bad.  But then again, there have been hardtails around since bikes have been made so they've obviously make do okay.  I've been playing around with the same idea as you but I'm not quite convinced yet to pull the trigger.

My plans are to make them interchangeable, by that I mean if I'm going to like a bike night or something then toss the hard struts on, going long distance toss the shocks on.

They'd probably work.  They would surely look better than the simple bar stock.  The solid round tube would match the round frame and swingarm better.  I'd suggest trimming one side of the mounts, top and bottom.  Then mount it were the trimmed side is against the frame and swingarm.  

Struts are very easy to make, install and remove.
Im amazed that people can sell these.
I made some up from 6mm thickness flat steel, drilled two holes in each piece of metal and cut/filed a nice radius on the ends.

The beauty is you can lower the bike very cheaply and replace the shocks if you like at a later point.

Its late here, (2am im still at 'work'), but I will try describe the steps:

1) Loosen nuts holding shocks in place (but dont yet remove).
2) Safely Jack bike to raise rear wheel of the ground (dont place jack such that you cant rotate wheel).
3) remove shocks (note wheel/swingarm will drop downward, but its pretty light weight).
4) Place various size blocks under rear wheel to raise up toward the mudguard until you are happy... This will let you get an idea how much you can lower. Dont leave less than about a half inch gap between tire and underside of mudguard. (When your wheel gets hot it expands..and you dont want it to rub). Also if you lower too much your pipe or pipe bracket may grind when cornering. I would suggest leaving about 1inch gap.

5) Measure the distance between the shock mounts and cut your flat steel to alow 'about' 12mm extra length metal (The intention is that this will give 6mm of metal around the hole).

6) Drill your holes in your flat steel (strut) and round the ends to make the job look tidy.
(I drilled out a hole only big enough to fit the threaded part of the bolt and cut a small piece of shiny stainless tube as a spacer to fit on the inside of the strut. Personal preference.)

7) paint, install and away you go.

BTW riding with a hardtail, is not as bad as some people make out. On many roads you wont even notice the difference as the front shocks absorbe the smaller bumps. I have a number of rigids...and as chops go..its the only way. (BTW I dont have a sprung seat..hate them, but that also is a matter of preference and its great we are not all the same)

Hope this info helps, I will share pics when I get a chance, as im sure my sleepy directions are hard to follow.
The above round bar struts look more robust than mine, but its the same principle.

best,
G.

You could try these.  
http://www.onlinemetals.com/merchant.cfm?pid=1090&step=4&showunits=inches&id=...

They are round 1" diameter x 12" long 6061-T6 solid aluminum.  At only $5.04 each they won't hurt the wallet if you don't like them.  If you wanted them 11" or 11.5" total length then they'll charge only 61 cents to cut each piece.  Not bad in my opinion.  

If you want something even stronger you can go with 7075 aluminum which is actually stronger than some mild steels.  

You can get flat bar as well.  The 1"x1.5"x12" 6061 aluminum bar is $10.05 each.  This is exactly what the seller "flightsimshop" sells on ebay as S40/Savage make-your-own solid lowering struts for $29.99 + $14.15 shipping.  They are blanks, just like you'd get from OnlineMetals.com, and you drill your own holes. Here's the ebay link:
http://cgi.ebay.com/ebaymotors/SUZUKI-SAVAGE-LS-650-S40-MAKE-YOUR-OWN-LOWERIN...

I'd recommend figuring out the center to center distance you want.  The shortest I can go on mine, center to center, with the rear fender lowing mod, is about 9.25"center to center.  With no rear fender lowering mod you can probably go down to maybe 9" or possibly even 8.75"  I think most people on here are using about a 9.5" to 10" measurement.  

If you want a half inch extra rod/bar above and below the bolts, then add 1.5" to your center to center measurement to find the total length needed.  Likewise, add 2" to your center to center measurement if you want 3/4" above and below the bolt holes to get the total length you need.  

Okay, I pulled the trigger on the solid strut mod after researching solid struts on the S40 and other bikes.  I decided I want round struts with the ends fully rounded.  After looking at the cost of material, purchase of a new drill bits, drill lube, time required to do it, going to my father-in-law's garage to do it (don't know if his drill press is powerful enough for such a job), the precision needed (especially for drilling the round struts), building a jig of some sort to ensure equal hole spacing and alignment on both struts, etc., I decided to have them made at a local machine shop.  I went to the shop yesterday drawings and one of the lower shock mount bolts for them to measure.  Were I to go with square aluminum I'd definitely do it myself.

They will be 1" round steel with the ends fully rounded and holes 9.5" on center.  Total will be $50 + tax.  It would have cost me about that much or more for the material and supplies to do it myself.  I'll post pics when I get them tomorrow.

Does anyone that's been around for a few years remember at all what kind of rear fender savage clay used on the orange bike? He hasn't logged on in about a year so a pm wouldn't help me