I bought a Leinen lathe a few weeks back only to find that it had a 3 speed motor on it, after speaking to a few people it turned out that my only real option was a rotary phase inverter.

3HP version - £500....!!!! ouch... and that was after knocking him down on price.

Thing is I can now run any 3 phase machine off of it (under 3hp) which gives me a bit of flexibility.

Hopefully you won't need to go down that route.....