Do a search on google for alternators and you'll find some companies that do sell a generic one. All you need to do is make a harness so that it'll fit in your car. Some even have a guide on making your own.
4alterstart.com can build one mralternator.com or alternatorparts.com may have one already. at worst you can usea generic casing like a denso, with the right mount type (side, top etc) and have brackets bent for your car. that's how I had to do it with the ford I used to use with a lestech alternator