Tisham Dhar blogged about his 3-phase synthesizer:
Finding 3-phase is difficult, convincing the owner of the said supply to test some home made hardware is even more so. After building a 3-phase energy monitor my testing options for it appeared very limited. So I set about making my own low-cost 3-phase energy monitor calibration system.
See the full post on his blog.
Check out the video after the break.