Well, you can't really 'fake' it.... you'd need a valid private and public keyset to sign an xbe. There are people who have done gross calculations and claim it can't be cracked with brute force in under 1000 years, given the distributive power of all the computers on the internet.
I'm finding that a bit hard to believe, but the point is taken... it's near impossible to crack it with today's computers.
Perhaps somebody at M$ will sneak out a key set? We do know some very intelligent people are working on whatever cracks appear in the seams of M$ key/signature scheme, just as the DSS was cracked on DVD through a mistake on the part of a software DVD program.
