Also, I think I should add that a split is inevitable.
If the Wikimedia Foundation chooses to not host it, those of us who believe a separate Wikipedia is nessecary will fork - not just linguistically, but the serious type of different-server-different-domainname fork entailed in for example Enciclopedia Libre (enciclopedia.us.es), wikinfo, wikiznanie.ru, etc. I'm not 100% sure but I think a similar thing happened some years ago when fr: was allowed to decide whether or not wa: was created, and eventually it was transferred to Wikimedia Foundation servers.
Basically, what I am saying is this:
No matter how much the Simplified users (and perhaps a minority of Traditional users) protest, there will be a forking. We (those supporting a split) hope it can be done quietly and without a real departure from zh: but rather one where interwiki cooperation will be possible and even frequent and not stressful.
However, if the Wikimedia Foundation decides that zh-tw: is not deserving of its own Wikipedia, we will pursue more radical measures, ie complete separation which will make interwiki cooperation much more difficult.
Please realise I am not threatening anyone, just letting you know that this is going to happen no matter what, and that really what we are discussing here is whether it can be hosted by Wikipedia and be officially part of Wikipedia, or not.
Best, Jin Junshu/Mark