S-trem and TransTrem are pretty much unobtanium at this point for less than $1500 JUST for the trem. They require a little teeny tiny bit more routing (just another ~1sq. in. on the back right side) to mount but the bulk of the footprint still works.
Jcustom still hasn't released their TransTrem copy, but their S-trem is AMAZING.
I didn't know JCustom was working on a TransTrem copy. This would be a big deal if it ever comes out.