Hi Scott,
Are you just trying to identify a mobile client by user-agent? If so, here is a recent discussion:
Detecting mobile/wap browsers via user-agent and other headers
http://devcentral.f5.com/Forums/tabid/1082223/asg/50/showtab/groupforums/aff/5/aft/86313/afv/topic/Default.aspx86381
Or if you need the full capability reporting of WURFL, making an API call would probably be best. If the database size is ~12Mb and millions of records, you probably wouldn't want to load it into an LTM iRule table. In current LTM versions for querying an outside resource from an iRule are somewhat limited. You could use HTTP::retry to make an HTTP request to a webservice and then use logic in the iRule to handle the client's HTTP request. Deb wrote an article on this a while back:
Conditioning iRule Logic on External Information - 01 - HTTP::retry
http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=105
Aaron