I dunno if this works for everybody else already, but it feels like it’d be useful to be able to jump to the first dir/file beginning with ‘Q’ by hitting the ‘Q’ button - like in explorer and finder.
Just a thought.
But then you wot be able to play notes in the diskbrowser…
How about if the disk browser has focus then you can use the type-to-find functionality. If another panel has focus, such as the pattern, instrument list, etc., then the normal note-playing behaviour is used?
Is this used for sample/instrument previews right now? (Not at renoise computer right now, otherwise I’d test myself)
If not, my humble vote is on searching rather than playing while in the browser. Especially now, with the beautiful “lock focus” feature, it’s alot harder to become stuck by accident while performing live or going wild recording. 
I didn’t know it was possible to play keyjazz whatever is selected in the diskbrowser…
In any event, both actions can coexist together. There could be SHIFT or CTRL or ALT for finding. hold ALT and type “GO” and it will find your “Go go power rangers.wav” that you’ve been itching to add. I use a similar control scheme in Total Commander and it’s pretty effective. A pop-up box appears with what you’ve written so far and you can backspace for correction, etc. All this can only happen if you’ve got focus on the diskbrowser though as many global shortcuts would be sacrificed.