#1
I was wondering if there existed a rackmount, pedal, or whatever, that not only was midi-capable but had the ability to program/create your own effects digitally (i.e. on a PC) and upload them to the device...

I doubt such a piece of equipment would exist specifically for a guitar, but technically you could take a PC sound device and hook it up to an amp if such a thing existed...

I can do quite a bit of programming in C/C++, Basic, Java, and a bunch of other languages too, and if I could get a device like that, itd probably be the end of my effects needs... ever...
Gear:

Jackson dk2m
MIM strat
peavey jsx 2x12 combo
Recording King RDC-26
Digitch RP1000
Crybaby 535Q
#2
The RP 250 from digitech has the ability to do that but you have to download it from the site. (i own one and its amazing)
"As long as I'm satisfied with my work, I'm not too concerned with what any critics think, but when I can stand on a stage and see a lot of smiling faces in the crowd, it makes it all worthwhile." ? Randy Rhodes
#3
Look into the Eventide rack processors, but be prepared to spend a minimum of $2,000 for even their cheapest unit.
Someones knowledge of guitar companies spelling determines what amps you can own. Really smart people can own things like Framus because they sound like they might be spelled with a "y" but they aren't.