The only functionality actually missing from the new autocomplete widget is the multiple-option. That will be implemented as its own widget, a prototype is here:
http://github.com/jzaefferer/jquery.ui-tokenlistFor replacing caching or formatItem and various others, use the new source-option. There are demos for
caching,
custom formatting, or even more
custom data.
If you use local data, "matchContains" is on by default. To search only from the start of each value, take one of the custom local data examples and put a "^" at the start of the regex.
It may look like its more complicated then before, but its actually much simpler to do all these customizations, as they are all in one place, and you're not fixed on a few on/off switchs, but can combine and customize whatever you need.