Several points. There is an aftermarket program that will do the Pana 624 through the SMDR port. I have no positive experiences with it; if you know me, you will understand why.

Panasonic just introduced the new KXTAW848. Feature highlights include:
1. Programming by computer
2. Ability to install up to four "cell repeaters" in a home, so that a conversation can pass from one cell to another as you move throughout the home,
3. Integrates with voice mail
4. Integrates completely with SLT devices, with no extra card required (Vodavi at one time required that. Avaya does not....)
5. Room to room intercom, natch
6. Speakerphone on the cordless (!)
7. Lots more.

Product is less then two months old. We got our first one just before EH Expo (good thing, since we ran training on the product there.)

The KXTG4000 is a consumer 2.4 ghz product. It's ok, but the first day is the best day, and performance will slide from there. As said earlier, do you want to be selling a product sold at Best Buy?

Lastly, Panasonic has instituted serious territory restrictions on lots of products, but Business Phone Products are not in that category. A distributor who can't supply the 4000 system to you is following rules that Panasonic has imposed. Don't dump on him/her. He's trying his best.