My experience gained today verifies the above, partially.  I did not shoot enough to slow things down with a strained buffer....

About 10 shots of the quickest my D200 will do were done in RAW, compressed RAW and in large JPG.   I perceived no difference in speed of shots in this simple hands on test.  I am not sure when I would actually need to do this sort of photography.

As for compressed and full RAW, the most meaningful testing to me would be to lay an uncompressed over a compressed version and see if differences are apparent in the highlights or elsewhere.