Problem resolved...
I finally decided maybe one of the system buttons was stuck or something. I removed the Wii from it's little cubbyhole to see if there were any buttons that I'd overlooked. When I pulled it out I see something completely unexpected. There was an extra black cord plugged in on the side. Apparently my Wife had played DDR at some point and managed to put the mat away still plugged in and the cord was neatly tucked back out of sight.
I don't own any GC games or accessories so it never occurred to me something was plugged in over there. I freely admit the problem was entirley of my own making and apologize for wasting the time of those who tried to help.
Thanks to all for the assistance. Now to get past that USB not recognizing issue, but I'll be going back through the simplistic mod from the beginning and I'm sure that will fix it right up.