I am a keen user (and unwitting promoter, it seems) of tiltback set ups. I started with two GK RB700 combos - great pieces of kit, apart from the castors disintegrating. They're all the amp anyone is likely to need. Having the cabs pointing directly up at me, rather than having the mids and highs blasting past my knees, was a revelation (especially with fretless). However I had to give them up after having back issues.
I then went to a lightweight solution but noone at the time was making tiltback lightweight cabs. Stands were an extra item to carry and didn't prevent the cabs from walking while in use. I had a look at old Trace and SWR tiltback design cabs but wasn't too impressed by the specifications of either.
However recently I've purchased a pair of fEARless F112 tiltback cabs and power them with GB shuttle 6.0's. Great solution so far although not cheap and I have yet to give them the full beans.