This might sound a little ridiculous, but I figured I would suggest it anyway. How about something along the lines of a onesie or long johns? Maybe if it was anchored by both being around the head/chest area and around the tail/rump area (so long as it didn't tug and cause discomfort anywhere, and had the necessary open areas to have freedom to "go") it would stay on better? I don't know, this idea sounds pretty goofy, but I hope it helps!
Wow, I wish I lived in your neighborhood! All we get here are moldy armchairs! Great job giving them a new lease on life, I especially love Starsky (and his Hutch). That glitter vinyl is great! I only ever see black and red around here!