It is my belief (but I'm happy to shown wrong) that the idea of 'Monotonic Containers' to provide a new allocator for vector to support a small block of memory is fundamentally not going to work, due to 2 limitations of allocators: 1) There is no support for in-line expansion (effectively, realloc which doesn't move if it can't realloc) 2) There is no support for an allocator to say "No, you can't have X memory, but I could give you Y", so it's hard to "exactly fill" a limited memory buffer. I have been working around this by implementing new special containers, which know about the size of a fixed buffer and therefore can make use of the space. I now think I'm probably going about this the wrong way, a much better way would be to implement: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n2045.html , or a variant thereof. The big problem with doing this "within boost" is that it would pull in a basically complete implementation of std::allocator and the containers into boost. In an ideal world, such a small and in my opinion useful extension would have been added to C++0x, but it's far too late for that now. tl;dr : Seeing as we are having a "what would boost accept" couple of days, would adding an (extended) implementation of a substantial part of the standard library be acceptable, or would I be better off trying to get this picked up by one of the existing standard libraries to pick this up (my worry being they may not want, quite sensibly, want to accept code which is not standardised). Chris