Last year around this time I started a Stravinsky list with the possibility that in due time it might be desirable to use the cataloging system on IMSLP. Carl advocated the idea of IMSLP cataloging numbers with Italian Baroque composers a while back, but I see no reason this same system can't be used also for more well-known modern composers who have no catalog already.
The main sources I used were Eric Walter White's list of works and Walsh's list of works. It was also reviewed by Richard Taruskin twice, who is an eminent Stravinsky scholar. (Needless to say he had his fair deal of correction).
The only problem is really that people may not be used to the catalog (obviously since it's new), and if there is
a mistake that surfaces months later for whatever reason, it might be a lot of work to renumber everything and move all the page titles. I can do it if that happens though.