It's not a common catalog-like site, as I see. Most relative to your needs is a «Freelance» project. It's an unofficial add-on to Cotonti CMS, that utilizes ability for two groups of users. First is posting some service offers, second search for it and buy some. But this project has a bit of disadvantages for you:
- it's not developed any more (as I know)
- it's oriented on russian market (so not numerous documentation is all in russian)
- and last — as it's not official pack you can not find sufficient support for it on our site.