My C# bootloader application is fully functional!  It can read, interpret, display, and write hex files, and erase, read, and write/verify the PIC, including program memory, EEPROM, ID locations, and config.

So now I can, in good faith, recommend that anyone interested feel free to check out the article, and try it out.  Feel free to point out anything wrong with or missing from the article, or any coding suggestions, or any suggestions at all for that matter!

I modified the structure a bit since the first versions, to make a little more sense, and to make it a little more flexible in the event that I ever want to make it compatible with other PICs, beside the 18F4550 it was made for.

I am already working on an improved version on the GUI side of things, to make it a little better for actual use, by doing things like running the time-consuming PIC read/writes in a separate thread to avoid hanging the GUI, and adding a few options here and there.  So far, I'm not planning to use it to replace the version I have listed with the initial article, since it's supposed to be a semi-introductory article and adding too many features would just make it more complicated for a newcomer to understand.  I expect it will end up as an addition on the last page of the article, after the important stuff has been discussed.