On Tue, 1 Oct 2002, Greg Turner wrote:
CHANGELOG:
- dlls/rpcrt4/rpcrt4.spec: Greg Turner gmturner007@ameritech.net
- flesh out some stubs.
Implementations of these and much more can be found in this patch submission, which was apparently never applied: http://www.winehq.com/hypermail/wine-patches/2002/06/0103.html
You can probably try to extract what you need from that patch if you want more rpcrt4 stuff.