OUTIGERI have the premiers rain pants that the legs are removable for shorts. I wore them for three days in Hot Springs in the rain and they were perfect. Allows for the heat to be released and you still stay dry.
I can see where releasing heat can be a major issue for you Tim. If one tied off the ankles on your long pants... well. Let's just say it wouldn't be pretty.
I can't wear the FJ shorts (not long enough)
eBay has a new pair listed: