viewtopic.php?f=2&t=69
It's not stated explicitly there, but you can retexture and resell your own vendor bases! They're fullperms.

If you have a fishing area kit, use your Proof of Purchase to get the latest version. Unpack this box: "(7S Boxed Stuff) More Vendor/Board Styles". The fullperms base for the clear vendor is in there, along with a manual that explains all about how to modify it, align it, and sell or redistribute it through OpenSeas.
If you don't have the fishing area kit but would like to try this out, send me an IM in-world and I can send you the base and manual. You won't be able to test alignment, but maybe a friend would rez a clear vendor for you to align the base with for testing.
The base's root prim of the base is microscopic and tricky; I had to set it up that way to ensure it would line up using the same coordinates as the clear vendor.
Also, on a related note, that same box from the Fishing Area Kit includes a clear contest board. We didn't bother including a special base for that since any builder in SL can easily drop a box or basic signboard behind it. I guess you could sell matching prefab boxes/signboards/whatever to go behind those, too.