How about placing the cursor there by default when no image is selected?  If that interferes with toggle keys (L & Z), then maybe use the tab key to place & remove cursor???
Pretty please?
No.  If I did that then users couldn't immediately use other keys to control the contact sheet without having to click into the contact sheet.
I know you're annoyed by having to click inside the Quick Search item but I'm not going to make a change like that and upset many, many more users.
Perhaps you could suggest a keyboard shortcut that isn't already in use?
-Kirk
BTW, these sorts of things are better handled in the Feature Requests section of the forums.  With your permission, I'll move this thread there.