Greg,
Looks like there is a great deal of misunderstanding how exactly SIP Trunking works.
Here is one example:
One of our remote offices have 35 users. Currently all of them have individual phone lines. Each line cost $23.60 per month or $826 total.
The local carrier refuses to do fractional T1 which means we have to do full T1 (23 voice channels) or $542.80 plus $3 per DID and so the total bill will be $653.80
Currently we implementing OCS with SIP trunk from Broadvox. We will pay for 15 concurrent calls trunk (15 x $12.75) + 40 DID (40 x $1) which totals $231.25 per month.
$12.75 per channel is for GoLocal which is unlimited local calls and 0.02 or so per minute long distance. I personally don't care about it because in the head office we will have GoAnywhere (unlimited long distance) trunks and all calls outside the local calling area will be routed via this one.
With my respect to SmartSip, in your case, you will pay $2000 for the software plus licenses per phone to connect 20 phones... I would buy 20 Snom phones x $100 each and get over it. Now, if you had 2000 Cisco phones, this is different story.
Drago