rpc client timeouts

[Roylance, Stephen D.]

I'm having the following problem with Samba 3.0-alpha22, AIX and winbind.
Whenever winbind is queried for information about certain groups, like
Domain Users, it fails to return any data and produces the following log
message:
rpc_client/cli_pipe.c:rpc_api_pipe(359)
cli_pipe: return critical error. Error was Call timed out: server did not
respond after 10000 milliseconds
as well as others.
 
My conjecture about the cause of the problem is this:
We have a rather large domain, 64,047 users according to wbinfo.
Returning the group entry implies fetching and returning the list of group
members.
Winbind calls into the rpc client, which starts fetching the list of members
The rpc client sets a timeout and starts pulling the list of group members
Fetching all 60k users takes longer than the timeout, the timeout fires and
the rpc client returns failure
 
I'm hoping that the solution is either:
The rpc client timeout can be made smarter, it could check if any data had
been received before it failed the request, or, 
I can statically increase the timeout somewhere until the problem goes away
 
Thanks in advance
-Steve