All this was back in the 80’s
Some one I know started to do this to a grem/jeep. I only saw it from the street in the garage; It never made it to the street.
 
I have seen a late 60’s camaro & firebird body on a Wagoner chassis, FB was on the street.
 
I started building a 68 Cougar body on a 69 Bronco chassis, it would move under it’s own power in the yard if I needed to move it but had a lot more work needed before it got on the road. Dad traded it for work done on has house as I was into other things after sitting for too many years.  
Sorry to say I don’t have any pictures of any of them
Dave ----

When I did the Cougar / Bronco I wanted the body to sit as low as I could get it, I did not want it to look like a just “dropped it on” so I channeled the body over the chassis. In side you could only see it in the rear seat foot well. I also had to add a few body mount brackets besides the stock Bronco ones, think I used hockey pucks for rubber mounts.
And yes I did have to make the Bronco chassis wb longer. I was also using all Ford parts when building it, this way if some thing went bad all I need to know was what it cam off of (Cougar or Bronco) and get a good one. Inside the Cougar would of looked stock other than the transfer case shifter and in that year Bronco it looked just like the Cougar shifter.
Yep big plans just never went all the way thru with them
When you get started take pictures and keep us posted.
Dave ----

its called an eagle kammback(sp?)

I like your idea.  The post before is a clear indication that it can be done.  I just want you to carefully consider how much work it would be to do.  I have a friend who used a Wrangler body and frame and used an all chevy blazer driveline.  What a mess!  It took him 2 years to do it and ended up selling it for less than half of what he spent on parts for it.  SAD.  
     It's probably fair to say that you could buy a Jeep CJ and fix it up as a CJ AND have your Gremlin as is for the same cost as what it may well take to combine the two unless you are a very good scrounger.  The combined value for the two (Jeep and Gremlin) will certainly be higher than a single combination of the two.  Far be it for me to play the voice of reason though  
     As long as you are looking at the idea realistically, it should be a cool project.  I believe that a late 70's, early 80's CJ-5 would be your best bet as a chassis, wheelbase wise.  I have had 76-79 5's for 15 years.  They are easy to work on, AMC V8s drop right in if it didn't already come with a 304.  If you lived closer to New Jersey, I could hook you up with lots of CJ stuff.  Good luck with it.
 
 
 
  

8 years ago when I drug my gremlilns home my Dad was taking about doing it to his Jeep cause it needs a body...There are a lot more pics out there of them...Just gotta look...