I believe in order for the Savage sissy bar/backrest to fit the S40, you need to change the fender rails as well.

As for saddlebags, my g/f has some rather large slanted ones (15 L x 6 W x 12 H) that she had the dealer install on her '05 S40 when she bought it.  The right side one was sitting on the OEM muffler and burned a hole but there's a good 1 to 1-1/12" clearance there now with the slash cut Screamin' Eagle muffler I put on for her.  The only other ones I could find specifically for the Savage other than the Suzuki clutch purse sized ones, are LeatherLyke's http://www.leatherlyke.com/srchbike.cfm?&DID=13&BikeNo=4341&Motorcycle=2004_S....  They're 18 quarts and measure a hefty 18"L x 8"W x 11"H and are lockable and come with a turn signal relocation kit.  There's also a helmet lock option. I called them and the sales person up front said no, the '04 Savage ones won't fit the '05 S40.  But I called back to ask why and spoke to a guy in the back who said, yeah, they'll fit, no problem.  I heard somewhere else that shorter bolts are necessary due to the S40's thinner fender rails?  I'm saving up for a set for her for Christmas.  Oh, and they sell the turn signal relocation kit by itself.