I read about making a gmail compose bookmarklet here but I guess this method works a little differently now that Gmail version 2 is out. The url I got as a bookmark from following the steps in this article looked like this:
This version of the bookmarklet takes forever to load for me and sometimes doesn't load at all. I took off the #cmid%3D1 and the loading time got a little faster and the page no longer froze while loading.
I continued removing stuff and changed from ui=2 to ui=1 and eventually got a significantly faster loading compose window with something that ended up looking like this:
This is the fastest version of the bookmarklet I could make that retained the auto-complete javacript for recipient fields. For a super fast version, you could switch to HTML version of gmail and bookmark the compose page, but I really like having the autocomplete for addresses.
To add my version of the bookmarklet, drag this link into your Bookmarks Toolbar:
** UPDATE **
This appears to be faster now: