Well I think I now have the info I need. That is, I have one option for cordless (albeit not out until April) and a couple of options for the low-end office/commercial which I need to have a look at.

Gut feel is that I'll wait until April for this new VTech cordless with PTT support, however I'm going to check with the vendor it does what the words seems to imply.

Thanks for the links/model suggestions to date guys.