Ok, to get the percentage readout in the menu screens, go to
Settings > General Settings > Display > Satus-/Scrollbar
then set status bar to on, and volume and battery display to numeric.
Some theme's wps (while playing screen) overwrite the status bar, but then include the info in a different way. What i did was to set the wps to disable the status bar, then used the code to display volume and battery at the bottom...


I hate the ghosting you get on the iriver when text scrolls, so my wps doesn't scroll any of the text. Just means that i only get the first part of the title if it's longer than average.
If anyone wants the files (they're all text files, open them in notepad to see the code)...
http://www.snatchbank.co.uk/filehost/raven/Mo23.wps (while playing screen)
http://www.snatchbank.co.uk/filehost/raven/Mo6.rwps (remote while playing screen)
http://www.snatchbank.co.uk/filehost/raven/config03.cfg (i don't go in for flashy names

)
Place the .cfg file in your rockbox\themes folder, and the others in the rockbox\wps folder, then load the config file. The wps is optimized for that font (ter-u12n) so changing to another one could make it display improperly.