I appreciate the suggestions. A few thoughts:
First, were I inclined to use a pocket watch, I would use Alton Sharpe's beautiful "The Devil's Watch" from Expert Hocus Pocus (a gem of a book that no one seems to talk about). An excellent version of the Burglar trick.
As for Topiting etc. -- I appreciate it. But one of the features that makes Tommy's routine so exceptional is the level of conviction made possible by Tommy's particular method. It is exceptionally clean and, to use a much abused line, looks like real magic.
Vraagaard -- Tommy spends (and I think this is appropriate as the place to learn the construction of the prop is from the book) very little time on the DVD explaining the construction of the watch -- he just outlines how the feke functions. The money is not simply attached to the watch -- indeed, it is not attached to the watch at all -- it is threaded through a brass plate which is attached to the watch by a custom brass hinge. Attached to this hinge is a strip of brass that must have an "S" curve to lie naturally against the fingers. To this strip is attached the piece that the fingers clip. This piece needs to look like a continuation of the watch, so it must be curved and must covered with watchlinks (which have to be ground down and then attached to the brass to be the proper thickness). So, while the function is simple and there is only one moving part -- it does require the ability to bend, cut, and drill metal.
I have thought some about alternative materials (and may make a maquette out of modeler's styrene), but it seems like if i'm going to go to the effort of building the thing -- it would nice for it to have the permaneance of metal.
Thanks again for all of your suggestions -- they are greatly appreciated.