I currently have 2 ADSL2+ connections connected via Draytek 120 modems which are hooked up to a Peplink Balance 380 WAN load balancing device.
Although the Peplink will do bonded VPN site to site (which allows it to combine bandwidth for data transfers between VPN sites), it is not possible for it to "bond" 2 connections outside of the site to site VPN environment, it is simply a load balancing device when browsing the rest of the internet.
One connection is a Vodafone Business 20GB plan. I get a fairly standard 21Mbps/1Mbps reading on SpeedTest.net
Now here is the strange part
The second connection is a CallPlus unlimited Business Plan. I am getting 30Mbps/2Mbps SpeedTest.net readings on this line. I have ran the SpeedTest.net over 30x using Tauranga/New Plymouth/Sydney servers and I also used Peplink's own SpeedTest app which allows me to test via downloading Apple/Microsoft/Adobe files and my own download manager speed readings. All of these tests are showing speeds greater than should be possible on ADSL2+??