Yikes. I just realized I forgot to make something important very clear in the text.
+1 Armor Class does not mean add 1 to the target number for you to be hit. I means your armor class goes up one category. If you aren't wearing any armor and you're weilding a Reach weapon, then your Armor Class is Light. Meaning the TN to hit you is 10, not 9.
Same thing with the monster powers of Thick Skin and Hard to See.
That's how you can get an armor class of Uber. But Uber +1 AC still equals Uber. 16 is the best possible TN to be hit.