An update - I went with the Victron converter for charging my Yeti 1000 Lithium off the alternator. It all works fine.
Here's the install in my Chevy Express -
http://imgur.com/a/7Ddec
I connected the remote switch on the converter to a fuse on the fuse box that's only live when the key is in the IGN position, with an add-a-circuit. Ideally there'd be a circuit that's only live when the engine is running, but I didn't find one, so I just can't leave the key in the IGN position without starting the engine. The ACC position is fine for listening to the radio and whatever else I'd want to do with the engine off.
The Victron converter louder than I'd prefer, much more so when the alternator is running and it's getting 14V instead of its nominal 12V, but tolerable, and can likely be mitigated with a bit of sound deadening in its install location.
If you go this route, be sure to factor in the 88% efficiency of the converter when sizing wire runs. I did not, and ended up with a bit more voltage loss than I had planned.