As one who spent the last 30+ years of his working life in the industrial automation sector, the last 15 working for the world's two largest VFD manfacturers, I will offer a few Q&A:
How did you arrive at the 3-ph motor choice ? First rule is you should choose a motor to match your power source. Plenty of 1-phase, 115Vac, 1/2 hp motors available
Bringing the 3-ph motor into the picture complicates your task immensely
If you apply a VFD, it needs to match your power source & motor voltage. I would give snot for any of the 'voltage doubler' drives on the market
Can a VFD create 3-ph out from 1-ph in ? Yes it can but you'll only be using 1/3 of the input bridge; therefore you need to get a drive rated at 2X your motor HP in order to not fry the drive.
Get an electrician to hook it all up ? Be careful, the average electrician who wires houses etc is as likely to blow it all up as you are. No offense to anyone, but controls stuff like a VFD is just not part of their regular MO... (ask me how I know that ! )
You need to seek out an electrician who does industrial-controls type work, and then one who has some drive experience as well. If you have any large industrial plants in your area, stop in and talk to the guy who runs the electrical dept, he can help direct you to the right resources
I could go on and on but I hope you get the gist of it.
Ideally, save yourself a lot of heartache and get a 1-phase 1/2 hp motor. BTW, Single-phase motors do not lend themselves to speed control as does a 3-ph motor. So if you feel you need speed control, take the advice of the folks above who recommended a DC motor. There are small 12Vdc gearmotors that will work very well for your purpose, and you won't be dealing with EXTREMELY LETHAL voltage levels as you would with a VFD.