Hi, Mark!
I don't think this is an UNC problem. If there is any problem, it is the same problem if I deal with "E:\" style pathes!
What I know is the following:
If DBC and releated tables are placed in the same directory - no path information is stored neither in DBC nor in tables. That mean you can place DBC and tables where you want - they know each other!
BTW: That is my real live experience from the last 5 years!
But may be, if you create a DBC using a UNC mapped drive, then path related backlinks are stored - but I never have heard something about that!
SeBaFlu