We’re developing a few sites at the moment (not going live ‘till stable release though) but we need to integrate Protx into one store and possibly Secure Trading into the other.
Secure Trading have told us that they are working on an integration themselves - get in touch with them and see what they say before paying a developer!
**EDIT** See this thread: http://www.magentocommerce.com/boards/viewthread/4617/