Changing 'owner' to list privlidged users only in bulk/query builder

Evenin all,
How can I rejig the query-builder and bulk to make the owner field
be free-text, or split it so it lists only privliged users and maybe add
another field for ‘requestor’ that is free-text?

I basically want to reduce the load time as I really only search on 

owners and occasionally on ‘requestors’, and would much prefer it
free-form for ‘requestor’ and priliged for ‘owner’.

What/where do I hack, or is there a patch for it already?

Adrian Carter
Technical Manager
Leading Edge Internet

Direct +61 2 6163 6162 Support 1 300 662 415