Clint,
Personally, I would be surprised if Kenwood dedicated a lot of engineering talent to a new, true full-duplex amateur handheld. The profit for them is not in the amateur world - but in the land mobile / commercial arenas.
I hope I am wrong, though!
At Dayton 5 months ago, Kenwood had posters in their booth announcing a new HT and HF transceiver for the summer of 2010. Of course, there were no details released at that time for either radio.
If Kenwood is simply updating the design of the old TH-D7 to be this new HT, that might be their way to minimize R&D costs. If they are able to replace the component(s) no longer in production with others, they may not make many other updates in the interests of saving money. The radio was still popular until it was discontinued, and remains popular on the used market now. I picked one up at a hamfest 3 months ago, and still need to make time to play around with it.
When the TM-D710 and TM-V71 mobile radios were released, Kenwood only developed one radio "box" for both of these models. They share the same FCC ID number, and the RC-D710 adds the TNC functionality to the TM-V71 (the RC-D710 does not attach to the TM-V71, unfortunately). Kenwood may be trying to stay in the amateur market, without spending lots of money to do so. It will be interesting to see what this new HT looks like, whenever it sees the light of day (or when someone puts photos of it online).
73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/