I've finally gotten around to insulating my 2-year old attached garage and
I'm thinking about heating it so that I can work in my shop with a little
more comfort.

The only three criteria I think I need are side venting (deck is on top of
the garage), low profile ceiling mount and the ability to work with a
standard setback thermostat. Sealed combustion with it's own outside air
supply would probably be a big bonus, although the seal around the insulated
garage is probably poor enough that air supply wouldn't be a huge problem.

There seem to be plenty of forced-air models that fit this criteria, but is
there anything else to choose from or a place with any kind of ratings on
reliability? CR doesn't seem to have anything and I'm not really getting a
lot of success via Google (although Google groups does have some food for
thought).

It seems that the "small" models run about 45K BTUs, which seems more than
adequate for a 30 degree temperature rise in 4300 cubic feet. I would
probably set the thermostat at 45 degrees and only warm the interior to 60
for getting into a warm car at the start of the day and otherwise only warm
it to 60 or so for shop work.