It would be the same effect as if you experimented with replacing one of your own limbs. Not pretty... :)
There are lens adapters that will fit *over* the EX1 lens and give you access to 35mm lenses- Letus, Brevis, etc. But unless you're a mechanical engineer with a fully equipped optical workshop the only effect you'll achieve by forcing off the EX1's lens is a broken camera and a voided warranty.
Quite honestly though- something like a Canon T2i/7D/5D Mark II would be a far more simple and cost-effective route to lens interchangeability.