Here is some reading:
http://www.technomadia.com/category/...y/lithium-ion/ (they have already installed these in their coach)
http://www.lithionicsbattery.com/rv.html
http://www.mastervolt.com/automotive...on/mli-24-160/
http://www.lithiumion-batteries.com/...deep-cycle.php
http://elitepowersolutions.com/
http://www.victronenergy.com/batteries/lithium-ion/
Lithium batteries are still in the development stage and hopefully prices will come down in the near future. But what I've read shows that they should be a better solution for our coaches, longer life cycle, lighter weight, more usable amps. I've read some other blogs of rv'ers who have installed these but can't find them right now.
Have fun