Cripes - yet another Barefaced user checking in! I use a couple of Super Compact Gen 3 cabs - each is 8ohms, of compact size, weighs 11kg, will handle 600 'clean' watts, and has a single high-performance 12" driver. I also have the BF Two10 that has the 'retro' voicing - 4ohms, 14kg, up to 500w. The minimum recommended wattage for these two cabs is 150 and 100 respectively, so I'm not sure how they would work with your AC50 - although I would guess you should be fine as the amp is a valver and the drivers BF use are highly efficient. These cabs typically come up FS on here at £400-£500. BCH also a nice, as-new Aguilar cab on here at the moment - which I mention because I know him and I know it's right.