Well, I do believe this SAGA is finally over. I'm not exactly sure what fixed it but for anyone who's watching the thread, I did the following.
I took the TPS off the carb and tested it. Initially, I wasn't getting any resistance change,so I removed it and tested the TPS itself on the bench. I still wasn't getting any change. I almost pulled the trigger on a new one, but decided to plug it back in and test at the ICM connection again. It started testing out fine. I tested it continuously for 15 minutes, open, closed throttle, everywhere in between. I don't know, maybe there was a lose connection when I started. Maybe that tiny little adapter to go from the TPS to the carb wasn't snug and it would spin. I don't know.
I removed the carb bowl again, and removed the needle under the float (the one that allows fuel to flow into the bowl). I did a fuel test both from the tank at the end of the rubber line for the carb, and through the float needle. Flow was okay.
I did take the All-Balls Racing needle out and inspect it. I didn't see anything wrong, but I did take a little sandpaper and run it over the rubber tip to make sure there wasn't a burr or anything else. I went put it back together and noticed the gasket was a little crushed on one edge. I played with it for a minute and the gasket seemed a little small. It's rubber, and it's brand new from the begining of this season, so I gently stretched it a few times along the long straight areas and got it to fit nicely in the carb bowl ridge.
Maybe when I put it back together last time, maybe the gasket wasn't perfectly in the ridge, and maybe under vacuum on the highway it was sucking air, causing my issue. I don't know. I'm guessing.
I also had someone hold the throttle open while running (approx 3k rpms) and I played with every single wire on the ICM and nothing changed.
Lastly, I looked at the ground (I know the 1800's have ground issues) and I took it off the engine/transmission case, sanded it bright again for good measure and buttoned it all back up.
Well, I took the bike down the road, expecting problems. There weren't any. I went down the highway, after about 5 minutes at 80/85, I hammered on it. I get her 110/115 indicated (almost wide open) for the better part of 5 miles and she ran fine. Sure, shes slow to pick up more speed after 100mph indicated, but that seems to be expected.
Just for shi*s and giggles, I put the Hard Krome exhaust back on, and ran the hell out of it again. No issues. All in all, I've done 400/500 miles in thee last 3 days (I drove 115 miles to beach for friend dough, haha). She seems to run great. She ain't a hot shot, but she runs really good, and she really comfortable and smooth under 95 indicated.
Anyway, I appreciate all the help and suggestions, and while I don't necessarily have root cause for this one, she seems to be better now.
Now it's time to ride, to catch up on the riding that I've lost in the past 3 months where is hasn't been running well!
Cheers everyone!