I was wondering that myself,When my Seeger front end gets put on, I would like the rear of my bike to be about 2" lower.Not sure but I don't want struts I would like to keep my shocks.

If You lower it more You will be scraping the bottom every time when You make a turn and there  is a bump on the road. This is the reaso why the bike doesn't have a centerstand.

Cutting spring steel essentially ruins it.

Basically, there are a few choices, most of them inviolve removing the shocks.  You can make struts for it, but that will wreck the frame b/c the left side where the shock goes is too long and would bend ojn your first bump.  You can hardtail it by welding in some steel between the frame and swingarm.  You can strut it with leafspring, but it will handle like cr@p.  You can buy shorter shocks from progressive.  Or you can find a shorter seat.  Evidently when it is hardtailed, you ned to convert it to a chain drive... not sure why.

Do a search for "hardtail."

My bike has the "shorter seat" option, but the shocks are stock.