another big problem with using C-incapable DSP chips is the fact that once these are obsolete, it needs to be ported to the new processor. C67x is a nice part. I use C64x in my day job and have used all the other 16-bit fixed point TI parts too (I work for TI). If there were free tools, I would have definitely prefered to use a C67xx part for PIC-A-STAR, which would have given me more MIPS to do more interesting stuff and also write everything with C.
There is a free TI-supplied C-compiler for the TMS320VC33 series. Download the University DSK zip file. It needs the University DSK to run the debugger, but includes a simulator, compiler, assembler, etc. Even includes source code for some of the tools.
73, Lyle KK7P