To the best of my knowledge, Kenny Brown Super Subs are your only option. You may want to try and contact SpinTech about their subframes. I do not know if they are full or not.
FWIW, I took the KB SuperSubs off my GT to put on Steeda full legnths(with torque box plates too), and then put my KB Super Subs on my girlfriends 99 auto/V6/Convertable.
I noticed no difference at all in my GT, but the KB's made an ENORMOUS difference in her little 'Vert!
If it wasn't for her car needing........SOMETHING.......I would've left the KB's on my car. Don't under estimate the KB's, they really did good in my opinion. My GT also has a 4-point roll bar, and after I put those KB's on the first time, they still made a sizeable difference even with the cage already installed/bolted/welded down.
are the actuall roush ones not full lenght? I don't know off the top of my head but I would just litterally call the companies.
I just know the roush cars have subs and run magnaflow side exhaust. i assumed they were full lenght but never look at roush parts due to the inflated price.
EvoMS and HANS are the only companys that have infomation stating their Subs will fit a side piped exhaust. People call Spintech and it doesn't turn out good for them