ajax autosuggest quick select

An efficient and fast ajax based solution to identify and select an item from one table. If no records found, display "not found" selected record should post to form. There are currently 11,000 records for this particular application, which presently has a filter inputbox and select input box. It is very slow and unreliable, most of all our users find it difficult. The desired solutions should be able to efficiently handle search through up to 30,000 records. Please provide an example of where you've implemented this type of solution before. Also include your estimated time to completion.