I can only help you providing generic help, don't have time to test everything myself. I've once tried to remove status bar, it wasn't hard but it didn't lead to expected results (view wasn't resized to effectively use additional space)
You'll have to modify the following file:
You'll need SD card. (modifying existing files on IM is buggy)
Create prsp.sh file in "database/system/PRSPlus" folder on internal memory. Put there:
mount -t vfat -o utf8 -o shortname=mixed /dev/sdmscard/r5c807a1 /opt/mnt/sd
cp /opt/mnt/sd/main.xml /tmp/main.xml
mount --bind /tmp/main.xml /opt/sony/ebook/application/resources/scripts/main.xml
Make sure you have unix style EOLs! (\n, not \r or \r\n)
The code above effectively replaces main.xml with one from the root of SD card without actually reflashing the reader. (You'll need to restart the reader every time you modify main.xml)
In main.xml, PAGE_GROUP is the view that you want to modify. I'd try setting PAGE_GROUP's top to, say 50 to see what happens. PAGE_GROUP also contains a number of other elements, with obvious names which you can move around.
Internal elements live in coordinate system of the parent.
Hope it helps.