I suggest you make a free 2talk account and have a look at what is possible.
Maybe someone from 2talk could say something on this thread? if they are reading.
Wendo: Well after some emails back and forward with WxC it seems they no longer do SIP trunking over the internet for anything more than home connections. Anything else you have to get a dedicated connection from them.
Wendo: The server is setup and I've been testing with IAX softphones initially to get around any firewall problems but once we get the incoming lines sorted, we'll be moving to SIP hardphones, probably Yealink T20P's, they are seemingly decent quality, with good reviews and have a good price. This means I'll have to open SIP to the internet, something I'd really rather not do but I can't configure VPN's at everyone house so this is it.