The only two places that seem to do a consistently good job, especially on seats, are Rob Budd and Paul Champagne.
Classic 9 Leather Shop Porsche Interior Restoration Automobile Reupholstery Craftsman
http://www.designpaulchampagne.com/PorscheLeather.html
I've looked for some time locally, SoCal, and haven't seen much that didn't in my opinion have some serious flaws. Most work is so obviously not factory quality, or maybe factory techniques, that its just sad to see the money wasted.