if the x'eye is anything like the multimega internally, then it uses a surface mount eprom for the bios instead.. you could still replace it, but it'd be ALOT more work and rewiring.
the model 2 is much harder to modify than the model 1, due to the lack of space and the bios being half hidden under the genesis connector. the model 1 is easier to modify, but harder to find.
if you are located in europe, I could prolly sell you a fully modded model 1 or 2, tho.