BT have never "supported" MLPPP.

Sharedband is your best bet for combining multiple ADSL lines, or some of the hardware based things like multiple WAN VPNs.

You reply to me..... why?

An intresting approach that i have used in the past which involves cisco routers.

Specificly if this is running over adsl (or other conenctions) and it is a VPN. you can use a cisco to join tunnels together. This works particully well for redundency + load balancing.

You can also connect different types of line together eg cable + xDSL at the same time.
It doesnt really matter what they are.

The downside is you need somebody who knows how to set this up.
The rotuers are around 2-3 times the price of standard kit.

The nice thing about this is you can scale it as well. eg you run out of bandwidth simply add another connection. It also scales very well when you have multiple sites with different requirments