An observer could check on a particular type of DC and auto-change each ones ID attribute to match some incrementing '$counter', but then it's clunkier than a DC only solution...

Quick test reveals that this is a feasible approach. I'm a little worried by the exponential increase in the number of components in the model, but I'll have to test and see whether that kills the performance.
I'll put up the sample when its working.

2 digit counter display

5 digit version