http://www.nada.kth.se/~matslina/awib/
is the only BF compiler I've seen written in BF and frankly it's quite large. All of the tiny BF compilers I've seen are written in C which seems more to demonstrate the compactness of C rather than the compactness of BF.
Comparing Forth and BF makes BF seem quite bloated. >>21 is right. BF is a childs toy- useful for stretching the mind and for personal amusement. It is not a demonstration of anything small or compact though...