My core Ork Army is Evil Sunz, I like lots of mek and vehicle action. But I also want a variety of modeling opportunities. I've been trying to find a way to shoehorn in other clanz without having a whole bunch of redundant models. The idea I've been going with so far is that any other clanz could just be warbands, specific units that would just be thematically the same, but just taken as normal Org choices. A couple of examples I'm gearing up for are Snakebites (Fantasy Boyz and Squiggoths) and Blood Axes (Russian Tanks and Grot Tanks and Artillery).
I've also had a hankerin to do some Tau-Looted ork models, like a band that has been scrappin with the Farsight Enclave for a while and picked up some tech. My current idea is to do a Wazdakka gang with grav bikers.
How about you? Are you mono-clan or ADD?