Hi Bob

A managed lease circuit is usaully just a virtual VPN. Allowing you to assign multiple IP's and in some setups manage your peers.

Honestly, I would stay with 2 normal DSL connections, and have a backup wireless or other connection type if you want good redundancy.

Ensure security of your UPS gear - generators. In the islands I have friends with similar setups, ( fiji for example ). They had 5 people unbolt the generator and simply walk right past them with it. They had no power in the area.... Kinda sucked, it was a 10,000$ diesel gen :|

Anyway, good luck Feel free to contact me if you have any other questions about home DC's. I have one myself