Just got mine cut at the local locksmiths. They didn't have the right blank in stock when I went in, said "just need to order in a Yamaha-type blank". Had it done within 3 days. Again, same size and shape top as original. Do check your new key on all locks when you get it - occasionally, a key might work in say the ignition but not fuel cap and/or seat. If this happens, can be a case of just lightly cleaning up edges with a suitable file, or have it redone, but you'll probably have no probs.
Modern chipped keys are a bit more involved.