Jelly, there are lots of places online that sell dried gourds. I even get some on Ebay, where you can see exactly what you're getting.
Here are a couple of links:
99.9% of the time you're going to get uncleaned gourds - since they don't know what you're going to want to do with them, it would be difficult for them to know how to cut them (in order to clean them out) ahead of time to suit your needs. The only time I've seen pre-cleaned gourds is when they've already been cut to make a birdhouse. They're really easy to clean, tho, just water and a brush.
I've been doing gourd crafts for about a year and am just getting serious about it now, so I'd be happy to share my mistakes and discoveries.