I don't know of any other suppliers of 24V starters. I'm sure there are a few more. Give www.sor.com a call and see if they have any used parts. They seem to have access to all sorts of vehicles from all over the World.
The other alternative is for you to find a motor / starter / alternator repair or winding shop locally / in-country. You'd be amazed at what these shops are capable of repairing, usually for much less than a new part.