Maybe just use . as namespace separator. MyNameSpace.SomeClass::_getInstance()->SomeDBClass->Query();
That will eliminate all resolution problems, it isn't used for anything than string concatenation, and it's one symbol. It's 100% better than \ and I think it would be better than ::: or :::: and so on. A point against \ is that it has special meaning in every programming language as escape character, so it is 100% bad to use it.
