Re: Dual ADSL connections
I looked into this a while back but we didn't proceed with it (LEA politics).
I don't think their are major problems with it - you have built in failover, except the lack of upload speeds and any other DSL specific problems.
There is a free linux version:
I know that linux doesn't support all the 'winmodem' types.
Cisco also do a router that can be set-up for bonded ADSL connections.
It might also be worth speaking with smoothwall about this or checking their forums.