How can I create a good autosuggest list with phrases?

[Shawn Heisey]

I'm at the point in my Solr deployment where I want to start using it 
for autosuggest, but I've run into a snag.  Because the fields that I 
want to use for autosuggest are tokenized, I can only get single terms 
out of it.  I would like to have it find common phrases that are between 
two and five words long, so that if someone starts typing "ang" their 
autosuggest list will include "Angelina Jolie" as well as possibly "Brad 
Pitt and Angelina Jolie."

My index is already quite large, so I do not want to add shingles.  I 
tried to use the clustering component, but that will only give you 
halfway decent results if you make the "rows=" parameter absolutely huge 
and therefore things run very slowly.  Also, it only works against 
stored fields, so I can only run it against the field where we retrieve 
captions, not the full description.  It's impractical to get results 
based on an entire index, much less all seven shards.

I'm OK with offline analysis to generate a list of suggestions, and I'm 
also OK with doing that analysis against the MySQL data source rather 
than Solr.  I just need some pointers about what software and/or 
techniques I can use to generate a good list, and then some idea of how 
to configure Solr to use that list.  Can anyone help?

Thanks,
Shawn