File Browsing by Alphabet (PROPOSAL)

(iriver only)
Enabled by clicking the joystick.(SELECT)
Disabled by clicking the joystick again (SELECT)

While enabled, the file selected is centered in the screen

Once enabled:
Up: Go to the previous letter of the alphabet
Down: Go to the next letter of the alphabet
Right: Lock the previously selected letter in place, and move the cursor to the next letter.
Left: Go to the previous letter, if/when possible