If it's 1400RPM, then it's most likely a 4-pole motor - the question is: have the manufacturers used a 4-pole for the extra torque or was it purely a speed related thing? Most single phase motors will have a capacitor start. Basically, the bigger the capacitor, the greater the starting torque.

You'll probably need to match the motor frame size and mounting type, but I see no reason why a single phase motor can't be used. The other option is to go for a 3-phase motor but use a VFD (Variable Frequency Drive) inverter to drive it. You can get some decent single phase in/ three phase out drives nowadays for around £100. TEC motors are decent and usually a bit cheaper than the Italian ones. Another option is to get a used 3-phase motor from a scrapyard. They're usually good motors which have been removed from industrial machinery. More importantly, they're about £5 each and can be driven by a VFD...