Is there a max number of names that there can be? If so the easiest
way is to set  a range name with that number of cells. Then set
the 'listfillrange' property of the combobox to that range name.

If thats too crude for you, you can set a dynamic range name, using
offset in the formula in INSERT/NAME/DEFINE. Then set the above
property to this range name. I'd be interested to
know how others would do this too, as in my experience dynamic range
names can cause problems.

I'm assuming theres a table with the names and the corrsponding
unique ID's, so you can use a vloookup formula in the other sheet to
get the ID according to the name chosen in the combobox. Does this
help?