If you don't have the new TT yet, you don't know your actual final weights yet. You cited empty weight on the TT. I hope you're factoring in the items, water etc you'll be adding.
I know I'm in the minority here, but if your weights are accurate I would do it. With the caveat that you make sure your tires are LT, not P rated as some half tons are, and The weight rating on the tires are above your actual weights. I would also upgrade to a better hitch like an equal-i-zer or similar, with integrated sway control. Don't go too fast, be cautious in wind, and down hills etc. you'll be fine.
Easy for me to say, I know. I tow a 7k TT with an F 350 diesel, but I towed the same TT with my 2003 half ton (shh!). It was about as overloaded as you will be, and I had no problems. I used it to my advantage though. Every time we went out, I'd say to the missus "we need a bigger truck Hun". It worked :B
