LifePower4 battery from Signature Solar is my favorite for building up a large scale system.  This is for people wanting to back-up their whole house, or go off grid completely.  Combine 2 or more batteries inside the enclosed cabinet for a perfect setup.  The 48V batteries from Signature Solar come in 2 versions, with or without a screen.  I don't think the screen version is worth the extra cost if you plan to use a central shunt anyways.