Well, I've decided to do some modification of my TI-84+. One idea that I had would be to plug an external power source into the USB port, and hopefully make it possible to add rechargeable batteries. In addition, there would be a way to draw current from the external power itself in order to run the calculator. It seems that I have just been going through too many batteries these days. While I have the innards opened, is there anything else that would be interesting to add? Perhaps a backlit screen, or something along those lines. Thanks!

color!!! New processor! more RAM and archive!!!

I feel that these ideas, while awesome, would be impossible due to the fact that everything is connected to the board with multitudes of pins. I could just get an Nspire and solve all of these problems, but I think it would be a good idea to be more original and creative. What do you think would be really cool to have with a calculator?

A solar panel would be nice. (not to be unoriginal or anything)

That could work... Perhaps build a little solar station so that way it could be connected to the calculator?

If I hadn't ruined the calculator I was working on and dropped the project, then I would have ended up making the screen flip out of the calc (but, of course, TI decided to integrate the LCD driver with the ribbon cable, so that wouldn't have worked out anyway (83+ may have been doable)).
where the screen was originally, a touch pad would have been placed (using same idea as Kerm's, just other side of the calc). I also would have used sticker paper to give the case a better looking art (because I suck at painting).

but, with the issue of power, I had a half-idea of using one of my 6v camera batteries (2900 kWh), which is bulky, but would last longer (i think).