I would like to know if it is possible to use network bonding (2 nic's that work as 1, for redundancy) and using DirectAdmin, due that DA needs a "static IP on a interface".
You can bond at the hardware level, but DirectAdmin still needs to run with a static IP# on it's main interface.
Generally if you use bonded connections you'll need to have your provider advertise your IP# with multiple routes. You can do it yourself with a custom programmed router that will create a new route when one fails, or perhaps running software in your server (though I'm not sure).
I'm not a network guru; if no one else replies you can start googling or post on a networking list.