No.
And I know you said non JB...but really, there's no reason NOT to JB. It's undoable in case you break your phone, so the geniuses never know, and...it's completely safe nowadays.
BiteSMS can search all SMS by keyword(s) (like Blackberries and such) and automatically highlights the text mesage containing the string in the thread. And it searches ALL text messages instantly.
It's awesome. Quick reply, quick compose...
All features Apple should have implemented from day 1. It baffles the mind why they haven't "borrowed" these ideas from BiteSMS.