I have seen someone on the board that did the conversion.. I can't remember his name on the board, but he was from somewhere in Alberta Canada. I believe it was a 4AGE and he was either in the process of, or had already done the conversion.
As for MSD ignition, I have seen a Smallport with MSD ignition, not sure how it was done but the car worked fine.
Here we go.. a quick search and I found him.. rezzle from Calgary Alberta, Canada. He did a propane conversion on his 4AGZE.
http://www.toyotanation.com/forum/t15161.html