I don't know any good machine shops local to you but the $15K number isn't out of line for a stroker build using all new parts. The last few engines I did were closer to $20K for parts and labor but they had upgrades such as ported intakes, high dollar oiling systems etc. You might be able to do a high quality stroker build for $10K if you have some parts left over from a previous build and if you stay flat tappet cam. As soon as you go with a roller cam the budget goes up a big chunk.