A little update, and thanks for the suggestions so far.
No luck with finding a Taiwan email contact, and as much as I would love to just dial the number, my phone plan apparently doesn't include international calls. I never had a problem calling Hong Kong when I was with Sprint years ago, but oh well.
I have actively been looking for the propane conversion kit for a while. I have yet to see one appear on ebay, but I will continue to check. I also check CraigsList nationally, and have responsed to a few ads from sellers/installers here and there. No luck, yet.
I am intrigued by the idea of making one, as I have a metal lathe, so turning an aluminum orifice to a precise size isn't an obstacle, but I am not certain I fully understand how to determine the size of the orifice from the gas pressure and BTU ratings, or if doing so from the numbers written on the side of the unit is even possible. I don't want to blow my house up, but it would be really nice to take a hot shower again some day. Can anyone offer some advice on orifice sizing here without the need for a lawyer? Ha!