Why not just go out and BUY a three phase converter?
You know that such a
thing does exist now.
As the person that started this thread, I can certainly explain why *I*
don't buy one.
The equipment I want to run will need about 45A per phase. If I had
an 85% efficient converter, I'd need an 80A 240V circuit. The entire service
entrance to my house is only 100A, and I use more than 20A of that for
lighting alone, not to mention the microwave oven, audio and video gear,
and modern computers.
Normal US homes are not wired for big old computers and their peripherals.