2
Mine is not exactly matchmaking, but similar (looking for people with your same name).
In order for XOOPS to work for matchmaking you'd probably have to find a module, or hack the core files like I did.
I had to add gender, age, country, name, last name, etc. It wasn't hard, but you do need to know some programming.
If you can wait, in version 2.2 you'll be able to customnize the registration process.
Hope this helps.