X-Wing Alliance Upgrade does this. However, as the leader of a one-man modding team, I imagine this must put a good deal of stress on the developer. But yes, it does give the fans a good overview, provided it is actually regularly updated.
A percentage value of each item is nearly impossible, though. Best you can do is to do as you say, and give each model, map, etc. a set of stages (for example 'Concept Art Finished', 'Modelling', 'Texturing', 'Coding', 'Testing', and 'Finished' in the case of models). Then assign a numerical value to each release (for example 'Release 1: 18/74 items ready').
But as I said, I'd not do it myself.
"One of the bitches actually gave birth while she was attacking, and her puppies joined in on the carnage."
--the awesomeness that is Boatmurdered.
Closed Alpha Test & Deth..
