I was a proponent of project specific repositories before I actually had to work with large scale system that consistently handled development in this way. This

I was a proponent of project specific repositories before I actually had to work with large scale system that consistently handled development in this way. This has me taught the hard way that managing transitive SVN externals (project A refers project B as external which refers to project C as external; I've had a hierarchy of 5 levels) is an incredibly tedious affair (tagging to get a consistent, pegged state of the main project is now a multi hour process instead of a single mouse click). That alone justifies a single repository. TortoiseSVN has a feature of pegging externals at a specific release when tagging the main project, but this only works at one level.