As I have stated before, I am amazed at how an organizations culture (read: dysfunctions or strengths) are reflected in their source control systems. This is a really a restatement of Don Norman’s assertion, which says, “The design of a software system reflects the culture of the organization that created it.”
So, not to belabor a point, but can anyone really make a case for a SCC model that is not a Branch-by-Purpose model? Here’s my guess. If you literally are unable to use this model in SCC to ship your software, I believe I can find a smell that is causing it.