It is more than just mono, it also requires wine to work well
with directx (see the stickies thread). I've done basically all that I can toake ai war as Linux compatible as possible, it now even runs on the 2.0 binaries instead of 3.5, but the last player who tested it still found it unplayable there. If there have been updates to mono and or wine in the last few months, might be a great idea to check it out again. But even once it is technically functioning, you still have the speed hurdle -- mono has been vastly slower than .net in the past for some things, though it is constantly evolving and has come a long way. So it all depends on where it is at the moment...