Jzilla,
No that isn't a flange I welded on, that is the stock Toyota surface. I very strongly believe (99% sure) that a CT26 from an MR2 (not, repeat NOT FROM A SUPRA) would bolt right up to that manifold, as Toyota likes to make many of their parts fit one another.
I was looking for an MR2 turbo on ebay (there are plenty) for a while so I could directly bolt it up, but then I decided that the Chrylser T3's are so cheap and so readily available that if my turbo dies I can go pick one from the wrecker for $75 Cdn and have it in the next day.
You (or anyone else) are looking for the CT26 from an MR2 or Celica. Whichever car had the 3GTSE engine. The Supra one (with the 7MGTE engine) is WAY to big for a 3B and it won't spool up properly.
In general, any turbo from a 1.8L to a 2.2L gas engine is perfect for the 3B. This includes some Volvos, Lebarons, some K-Cars, Dodge Shadows, New Yorkers, Daytonas, MR2's, Celicas, possibly a turbo from a 22RE (not quite sure about that) and many others that I can't think of this early in the morning. I think kits for/from some Hondas would work too.
Craig.