Sun does something like this (Score 1)

Sun have a program called SunVIP (Vendors Integration Program) which does something like this. Basically, they will go back & forth between their own tech support and your other vendor to track down the problem.

Main issues are:

1. Your other vendor needs to be on Sun's list (includes IBM, Oracle, Sybase, 3Com, Cisco)
2. You need a fairly high-level support contract with Sun (& probably the other vendor)

More info at Sun's support page.

Disclaimer: We haven't used the service - I just heard the spiel at a Sun presentation & thought it was a rare example of common-sense.... it may not actually work :-)