Please see the discussion in the comments to the question.
I would suggest one opportunity for code reviews. You can add another open-source product, Trac:
With Apache, it can be integrated with Subversion very well. If you do it, you can use it as a regular issue tracking system
]) and project management system
]), which will give you convenient opportunities to carry out code review procedures in a very organized manner, among many other things. You can cross reference any artifacts stored in Subversion and present them in the Trac Web pages as regular Web references.
Actually, Trac is based on Wiki and can be used as a general-purpose Wiki engine. It's very good for writing individual, and, especially, collective documentation, especially development documentation, but any other kind of documentation as well.
In fact, this modular approach with different but well integrated open-source providers is much better then monolithic approach.