Sorry, no help here. The cobra pan is the only aluminum pan I can think of. At least they look cool.
Funny you should bring up oil pans. I just found out the hard way that not all front sump pans are the same. While dropping in the 5.0 last weekend, the engine wouldn't slide back onto the tranny like it should, when I got under to look, the pan was hitting the crossbrace.
I pulled the brace and will be putting spacers in to clear. I would have used my old pan--drain on the side of the sump, but it was stripped out. This pan was from a salvage yard, and the drain was in the back of the sump. Stupid me never thought they would make the sump any longer because of that. Sorry to run off into my own little world there....been a long day. Ready to finish this engine up and drive my car again.
Good luck finding a pan. Bummer about the rear seal.