Alright, now Opera doesn't allow me to choose any "other" search engines to be my default.
Is there a way I can turn of onmibox search completely? No search engines at all.
Basically what I am interested is to get my local intranet DNS to resolve the keywords i type in omnibox, I'm not SEARCHING for anything.
Any help is truly appreciated.

Look for a way to reroute the default search engine domain's IP using the hosts file or something in your modem/router.