Plugins - RecordSelect
Add to favoritesUses AJAX to create a searchable, paginated, full-HTML replacement for a box. Maintains a hidden field with the record's id.
http://code.google.com/p/recordselect
http://recordselect.googlecode.com/svn/releases/record_select
Rails' (MIT)
Assets

Not working ok in Opera 9 - incorrect XHTML/CSS (maybe usupported JS also). Opera 9 is the best browser overall and is usually the last browser that fails valid content.
Looks like there's some overlap with modelautocompleter.