I really like the Polaroid 100 automatic (tripod mount, flip-down finder, decent lens, battery still available). And if you haven't already, try the fuji 3000B. I love that stuff!

I would also second the recommendation to check out local thrift stores. I've picked up a couple of pack film cameras (100 auto and 330 with a whole bunch of accessories) for less than $8.00 each.

As far as the battery issues go, there is a lot of info online for converting these cameras to use AA, but I just buy the proper battery since it only runs about $10.00 and I figure it will last several years. Freestyle sold it last I checked.