Last night I decided to swap out the bottom bracket from the one that I repacked. It was feeling gravelly on the left side again, so I chucked it and replaced it with an FSA MegaExo ceramic BB.
While the bike was torn down, I also chucked the 54T chain ring--it was at the end of it's service life, too. I had a brand new spare 53T Ultegra chain ring just waiting to be mounted.
After cleaning up the crank, installing the new chain ring, checking that the FSA BB would work with the Shimano spindle, and installing both the BB and the crank, I yanked the rear wheel off, opened the hub and cleaned/greased it.
While the wheel was off, I yanked off all but the first layer of Gorilla tape from the seat tube and rewrapped it again, this time with more re-enforcement to the aft side of the tube. I finished the work with a good cosmetic wrap of electrical tape--same stuff I use to finish my handlebar tape. The area is very stable and since that tube is in compression most of the time, as long as alignment is maintained, it should be relatively "safe".
In the meantime, I will look for a new -something-. I keep vacillating between building up a frame on my own using parts from the Giant or getting a brand new pre-built complete bike.