Yes, playing around with Fsk will definitely yield better results than my approach, as will your approach (PRS+) of hacking around within the ebook setup by using javascript/xml.
Truth be told, I'm doing this for the fun of it. Since I got my reader and installed porkupan's software, I've learnt a lot about the linux kernel, drivers, ELF executables, filesystems, reverse-engineering, dynamic linking, polished up my python skills a bit, got to code in C again, refreshed my knowledge of ARM instructions and got a cross-compiler installed. It's awesome fun, even if drawing to the screen is all I have to show for it
On the other hand, I investigated the javascript/xml hackery that is the sony software before I started on my current path. I wasn't really impressed with it, but more importantly, I was completely uninspired. There's hooks coming in from everywhere, being thrown around, functions being defined in xml and then called from javascript, strange vm.xml files needed, etc. The knowledge gained this way is not so exciting for me, as I'd only learn about the sony ebook/fsk setup. Brushing up on javascript might be interesting though, so I might take a look in a while and maybe even try help with your PRS+ efforts.
My inspiration or lack thereof doesn't have anything to do with what I think of your efforts though. I am seriously impressed with everyone who got PRS+ going.
Running shell scripts from the firmware on startup I can indeed do. What I would really really like to know is if there's a way to put a hook into the whole fsk/xml/js thing so that it would run a script from an SD card when I insert one. Whether by copying it into /tmp first or not, doesn't matter. I can't figure out how to make a hook that responds to the insertion of an SD card. I would very much value your throughts/advice on this matter.