I currently look after two phone systems (Avaya and Cisco) both of which are making all calls primarily over 2talk SIP trunks. One site has Snap VDSL, the other has a 'dedicated' CallPlus Naked ADSL2 connection
There isn't much information around about it other than the pricing page on the 2talk website, http://www.2talk.co.nz/access/
Basically it looks as though they are providing xDSL connections with a private 2talk IP address by default which would improve security somewhat as far as attack surface. Also means that internet connection wouldn't be as useful for much more than web browsing. On some plans for $10 extra you can add a public IP. I suspect for most users of this service, this 2talk access connection would usually be dedicated to VoIP however.
The plans for work start at $60/month for a naked ADSL 'voice trunk' which has no internet access, or for $95/month you can take that up to 300GB.
What I love about this idea is that in theory it should make the 2talk SIP trunking experience even more reliable. We have been having outages every couple of months through Snap, seems to be less on the CallPlus line.
As soon as it was announced I emailed their tech support asking a few technical questions and got an efficient 10 word response which told me
1) All products are Naked DSL
2) Telecom wholesale product is EUBA 0
3) They are using port based authentication
I still don't know exactly what they mean by port based authentication - I was trying to find out whether I would have to reconfigure usernames and passwords on the ADSL modems or if it would just connect straight up as soon as they took over the connection. Hoping it is the latter but what happens to PPP then...
Anyway, I look forward to hearing users experiences as they come up, unfortunately I probably won't be switching over to it at this stage as things are working well as they are so no reason to change.