Typing out a list of good gunsmiths to do the project for you would be a very long list and we would run the risk of leaving out someone and making them feel bad

So as Ned said, look around here and take a look at all of the nice custom guns and you will see that each smith has a style that is a little different from the next guy. You may prefer one style to the next, or you may like them all (like me).
Any of the smiths that post here and/or are members of the LTW Board will do an awesome job for you. There are also some very talented smiths that are not found here, you just have to do some looking. Keep in mind, good smiths are backlogged for a reason, they're good. I'm not saying that a smith that can get you started tomorrow is no good, but research who you are giving your chunk of change to along with your parts or gun.
Any smith that builds 1911s will know what parts to get for a 9mm 1911 build and any other parts for that matter. A Caspian slide and frame are a great start for a full custom build. I would suggest letting the smith get everything but the frame. If a smith supplies the frame and builds it into a gun for you I believe that he has to charge the 11% federal excise tax, but if you get the frame he's just selling you parts and labor. I would also get it with no machining done to it, that way the smith has the most metal with which to work.
I could go on & on with the parts I like to use for building, and what I think are good parts, but truth be told it's best to let the smith have free reign with the project. Choose your smith, discuss with him what you expect from the gun & it's usage and let him/her know if you have any specific preferences, like an Ed Brown beavertail over a Wilson, or short trigger over a long one, and let them go with it. The person you choose will most likely be an artist trapped behind a work bench loaded with frames, files & boxes of parts so it's best to let them do their thing.
BTW, the custom images forum has a little bio of each of the smiths involved here along with some awesome pictures. Not to mention, the custom forum has some super sweet images.
Good luck and enjoy.