are there Shift+Fn+key combinations in Maemo??

Anyway those are Qt standard QTextInput fields, I have no control of that. That would be a Qt problem, not a Yappari problem.

About the searchable contacts, they are searchable. Select any contact (so the current focus is in the contact list) and then type letters, it should jump to the contact which the first letter is the one you pressed.

EDIT: I could eventually add a quick search field or something...