I also wanted a starter and an alternator if I could ferret out a bargain. I haven't had any luck on an alternator yet but I did find a source for a starter. I bought a Kubota starter from a supplier to the trucking industry. The block Universal uses is a Kubota block and this block is used extensively in the trucking industry for refrigeration units.
It was well worth the effort of digging around the internet. I'm still trying to find alternators for a reasonable price. I don't need a starter or an alternator but it'll be comforting to have spares when cruising a long way from home.