You can set up as many projects as you like in ProjectLocker. Projects can be managed according to your development style and needs. Generally, if you will be sharing lots of code between projects, it makes the most sense to use one large project instead of several separate ones, using Subversion permissions to restrict access by directory within the repository. If you don't expect a lot of overlap, or you have different teams working on completely different projects (i.e. for various customers), you can create multiple projects to keep them separate.