OK, since there's interest, here's some more info on my fridge 
customization for Bus living:

I gutted the existing fridge cabinet between the sink and the closet. I 
put a fake bottom in both cabinets: remove the bottom for "deep storage" 
of car parts, odd tools, etc. The top part of the two cabinets are 
convenient for dishes or clothes, whatever.

I don't think one could easily install a propane (or any) independent 
fridge in the old cabinet. The way Westfalia separated the fridge 
components from the box to keep it narrow ain't really common.

The chest fridge I bought is the same height as the black tire well on
which the passenger seat is attached (and about as wide). The fridge is
not fixed it; just sits there like a cooler, perfect for sitting on while
cooking dinner or as a step up into the pop-top. (Of course, you have to
get up to remove things from the fridge...) Yes, the passenger seat still
rotates. 

I intalled a T-fitting and another propane hose under the Bus and into 
fitting mounted on the back of the tire well (similar to the one for 
the stove). I attach the propane hose for the fridge to this fitting on 
the inside of the Bus. (So, when I'm not living in the Bus, I usually 
don't leave the fridge in.)

Safety:

Yes, one should have ventilation: open the window :) Seriously, if one is 
concerned about safety, you could run the fridge off of the battery while 
traveling and on propane when parked (with the window atleast cracked.) I 
personally have driven from Belize to Canada with the propane burning and 
slept in zero degree weather in ski resort parking lots with the fridge 
on and all the windows shut. (This makes for a lot of ice on the INSIDE 
of the windows, though...) BTW, the fridge runs on LP, DC, and AC.

Performance:
At temperatures above 90 degrees the fridge just keep things cool (forget 
about ice cubes.) If you keep the sliding door open in windy weather, the 
flame tends to get blown out. (Yes, there's a safety cut-off jet.)

How to get one: 
Beats me. I bought mine from a propane supplier in NW
Quebec. (Alot of propane fridges up that way) for 450 Canadian (ouch) five
years ago. The brand name is Dometic: they supply most of the big fridges
for big momma RVs. So go to your local RV store and ask to see their
fridge catalog; you might be able to special order one. An RV guy called 
Dometic for me and said that they no longer make my particular model 
though... 

Whew, I didn't know I could be so long-winded. Respond if you want to 
know more about making a Bus a home....

--------------------------------------------------------- 
Morris Arthur 
Environmental Sciences and Engineering
University of North Carolina