Sounds like an interesting idea, but on second thought, that requires the module to be XML aware and network aware. I don't think these things belong into it; if I go there, I rather offer a clean interface for updating the @table and let the module user do the rest. Adding a sample script to the distribution that uses that interface to import an XML table might be a nice idea though.
Update: Actually, that sounds like a very nice idea. The sample script could import currency data from somewhere. Of course, it should carry a disclaimer, since currency calculations should not be done using floating point math when actual money depends on them, but it would still be a very nifty demonstration of the module's design.
Makeshifts last the longest.