When I re-did my stereo/battery bank setup last year I did a lot of research into chargers as well. Everyone I talked with (Earmark, Pro Mariner, etc.) said I needed a 3 bank charger since I was running 3 batteries. (1 - starting 2 - house) Even though the house batteries are wired parallel making them one big battery, the folks at Pro Mariner said a 3 bank charger would still see 3 separate batteries. Don't ask me how this is done, and they may have just been blowing smoke up my ass, but that was said by other manufactures as well.
I eneded up going with the Pro Mariner 20+ Gen 2 http://www.pmariner.com/productFeatu...oductNum=42021
I was told I really needed a 30 amp charger to handle the amp/hour loads I had, but costs were dramatic and I never drain my house bank so I went with 20 amps instead. So far I've had zero issues and been running just under a year with that setup.
Here is the 30 amp charger I was looking at.
Hope this helps!