Indeed, keeping a separate REAL starting battery is the preferred way to go these days.
Re: charging, one of the simplest and most effective ways to keep both the starting battery and the house battery bank charged is to connect all charging sources to the HOUSE batteries, and to use a simple device which senses a charging load on the house batteries and diverts a bit of it to keep the starting battery topped off.
I've used such a device for several years with great success. Mine is a Xantrex EchoCharger which puts up to 15A into the starting battery whenever it senses at least 12.9 VDC or so on the house batteries. It is cheap, simple, and maintenance free. There are other manufacturers who make such devices as well.