Updated: 10-Apr 2008
I should really add now that I spotted a couple of mistakes in the bundle which have been fixed. If anyone uses this and spots anything amiss - let me know and I'll sort it.
I've just finished attending the AIR tour and during the final (particularly funny) presentation, I completed a TextMate plugin that has full API completion support.
It was scraped from the JavaScript API reference pages.
I'll post more info that I've learnt - and probably turn the API scrapper (via jQuery) in to an AIR app if anyone wants it.