May be "WIKI-thon" or "wiki-mashup" or "wiki-sprint" (typical FOSS community event styles) could be a more acceptable name. The idea is really good but we need to do some basework.
From a branding perspective, using "thon" would probably work well and add some consistency to other Wikimedia event. For many years there have been all-day coding events that are called "hackathons" but a couple years back we decided to try "codeathon" (because some people out there still thinking that "hacking" means you are doing something malicious). Therefore something like Wiki-thon, edit-thon, etc., could work well and is a term that could be picked up by other Wikimedia groups worldwide when they host or inspire similar events/initiatives.
--Kul