I'm almost positive I've seen a document on Cisco.com that talks about putting both a WIC/T1 and VWIC/T1 in the same 1700 series router at the same time.
I can't find it again though! I'm thinking I might have been thinking this stuff up.
It is possible to have both a WIC-1DSU-T1 (for data) and a VWIC-1MFT-T1 for a PRI in the same router at the same time right? (1751-v router)