It will have to be a signed application to avoid so many prompts. I still havent seen such app but it might be there.
There is a folder navigation example in the current Java Developers Library under "Developer Guides -> Data handling" section http://www.forum.nokia.com/info/sw.n...s_Library.html
Regarding the second point:
It depends on the commands you add to the displayable. In case you don't know it, you use the Command class to add functionality to the softkeys. What phone are you using?
Adding to what rincon told:
Command buttons placement is totally depend on the command type and priority. The placement of commands differs in phones (for Nokia it will be one standard for SonyEricsson other). but you can control the placement of the command by changing the command type and the sequence number.
for eg: if by default Command.EXIT will come in RSK, and you want to make it available in the LSK, change the type to Command.SCREEN or Command.ITEM like that. But this will be against the normal UI specification of the mobile.