Stirling engines can certainly be used to generate electricity. The most efficient scheme for solar power uses a parabolic concentrator dish focusing onto the 'hot' plate of a Stirling engine. The company Stirling Energy Systems has built their pilot plants in California. The peak conversion efficiency of this scheme is around 50%, which no other solar technology - concentrator, PV or otherwise - can match. SES's organizational and financial problems as a company aside, the solar concentrator - stirling technology should be scalable for home use, and you can D-I-Y -- the most difficult (or expensive) part will probably be building or buying an appropriately sized Stirling engine and connecting to a generator or alternator.