http://www.imperialconflict.com/forum/viewtopic.php?id=128595

but to give you an easy answer, revalons are a good call.

if you insist on having a custom race...

50% income bonus is obvious
as is -30 on attack
you're going to want to have a decent research bonus
magic is less important but will still need a decent value, it will depend what ops you want.
speed should be as low as possible.

tax offices are vital.

EDIT: i forgot pop growth, which isnt important at all for CF'ers, so -30.