I know 'tis a bit late, but I tried the procedure having all the necessary audio tools. Lo! and behold, the results are.., well, vasudan. Ish. I don't have mr McPherson literally on speed dial, so I couldn't ascertain if I succeeded, but by semi-reversing the process I got to hear what the original source sounded like. At least close enough.
My conclusion: basically, you can make do w/ any kinda of foreign language. Foreign to the english nunciation, that is. Pick a random page from, say, the latin or esperanto WikiPedia, record it with an english diction, apply vocoder + EQ. Record original english in a monotonous (perhaps semi-british

) voice. Mix vasudan/human in a 50/50 ratio. Repeat. That's it.
I could relatively easily create the necessary sound files, if ya ST:R guys need em. Just a thought.
Cordially,
~Selectah