If you load balance you will have 2 IPs. In situations this can - in theory - cause problems, some websites might refuse the same session being initiated from 2 different IPs. One thing you could do is have a VPS and create 2 tunnels to the VPS, then there recombining then into one connection. This is called Inverse multiplexing:
http://en.wikipedia.org/wiki/Inverse_multiplexing
VPS servers monthly rental are quite cheap nowadays (starts $20). I am thinking of getting one for my hosting needs. If you're interested we can try to implement the system that I described on my VPS, in a way that will satisfy us both.
The advantages over peplink:
- You will have the total of bandwidth available at the same time (ie approx 512 + 512) on the same connection. I'm not sure how peplink does load balancing but I think they do it by distributing connections to the various IPs, which as I pointed out before can cause problems and also it means that you can't have more then 512 on one connection. The only way you could have more then 512 on a download is by doing simultaneous download of multiple file chunks in a download manager (what is called download accelerator).
What you need is a computer connected to both ADSL accounts, preferably running linux (I dont know if what I described is possible with windows). It will act as the router/gateway for your network.
Regarding your question, I think someone answered it in the past. I think you can connect your account from another phone line if you want. But I want someone to confirm that.
