Yeah, I'm starting to think that the HP80's were not the best tank investment to make - though I feel that we got a good deal on them so should be able to recoup much of it when it's time to upgrade! (Tanks: The only thing in diving that sort of holds it's value!)
I honestly hadn't thought of tanks as a way to make ballast more useful, but that makes a lot of sense! And more air as a nice side effect! Sadly, that's probably going to wait (weight?) until I can convince my wife/buddy to try going dry too. It's already sort of working though - she's jealous that I'm already blowing bubbles this year, when she won't usually dive until June when the water gets a little warmer But... having the better tanks option in my back pocket will come in handy since she's already a little leery about the amount of lead that going dry costs.
I'm already seeing the slippery slope of going dry. After the 1st weekend I went and ordered dry gloves, and now I'm on the prowl for alternate undergarments for when it gets warmer. I'm already thinking of what I want to do next time I get a chance to go somewhere warm.