I sent my stock seat to C&C Seats in California to have it redone with a custom cover. C&C seemed like they could have done anything my imagination could come up with.
There were many color choices, fabrics, and stitch patterns. Turn around time was very fast too!
Most any auto upholstery shop can do it. Try looking around in your area first. JS
Not knocking guys who do cars or furniture but motorcycle seats are a totally different beast all together and require a lot more attention to detail so I would recommend asking to see good pictures of their work and ask about the materials they use. You can buy cheap vinyl all day long at $6 a yard and make cheap covers that look good but don't hold up to the stress motorcycle seats endure.