Maybe I'm missing part of this, but can't you just create  the column  you
want on both lists and populate that with whatever data you need to identify
the elements, then in the workflow  call that data?

You would think, and I have already tried this route, but my workflow  errored
out saying that it couldn't find the list  item to update. (I guess it didn't
look hard enough.)

we do this all the time. BUT, the item(field,column)((hate this SP
vocabulary))is always a copy(via WF step) of a SP generated ID. Maybe these
are long  ints or some special type?

Well, I found two solutions to the problem  I was having. One was being able to
identify the workflow  Item ID, and that is what I was looking for. In case that
doesn't work, there is a feature on codeplex that will allow a column  to require
unique input. Although SPD would bark and scream about not returning single
results, etc. This could work also, depending on the information that you
assign. The documentation for SPD is spotty, and makes it difficult to find the
exact information you are looking for, but I got the issue  resolved. Thank you
to the group for the help. (I couldn't do my job without you guys.)