Hi StephenR, I tried the D800 and didn't think it was delivering the rich warm bottom end I get from my Mesa boogie walkabout. After trying the Darkglass again I have to say it does sound good but this time there was no wow factor and on that visit I found the sound was a little cold and less full in the bottom end, something I could not get the salesman to understand or accept. But then he plays rock bass and I play more reggae and Jazz funk so our perception on what is the right amount and nature of bottom end is widely different so to that end I couldn't find anything that was strong enough soundwise to part with that much cash. So best stay put.
In the end I decided that since I had a second F1-x sitting around that I previously used when I was experimenting with bi-amping, It would be better to use that.
I ended up getting a SYNQ 1K0 class D Power amp which is 1U and shallow rack so I was able to use my SKB shallow xrack case and build a 3U setup with my DS-5, F1-x and the Synq power amp. I've used it on two gigs so far with my barefaced cabs and it sounds great.