My understanding of Rich's words "subdelegating internally" would
be delegations for corporate lans, pop devices, dialup pools, and
so forth, rather than customer assignments. Depending on which
he meant, the two roles are very different.
Having said that, we are migrating to QIP for everything. 
Well in the system I developed we basically used it for all of the above since we needed the same sort of information to justify our assignments to the APNIC when we came back for more. The system could identify an infrastructure request so it could be more lenient with respect to requesting second opinions but our customers would have been unimpressed if there was one set of rules for them and another for us. Of course the internal clients (marketing didn't like it when you said no but that's why you have someone further up the chain than a low level NOCer making the decisions.
Mark.