I thought I'd start this post for people that are looking to do a complete chassis swap instead of a piece by piece upgrade. There have been many different donor vehicles used to date. I am familiar with using the Wagoneer.    http://www.cardomain.com/ride/2451568
Post or link to what you've done or seen done. This could become a good resource thread for others thinking of a chassis swap.  

Here is an interesting chassis swap. It's a '50 willys wagon/'76 Scout II looks excellent to me. check it out at;
 http://www.thefcconnection.com/'50_wagon.htm  

ok... so i've found my next project... in another ten years...newer dodge w/ the cummins this time...  

What have you gotmike? You might like this one,  It has a J20 frame and a diesel motor.
It is is at http://community.webshots.com/user/p14175  

Here is a nice  '53 wagon/ '98 tacoma swap.  http://www.cardomain.com/ride/2200259  

here are a couple that I found at; http://www.willysonline.com/
'59 wagon/'78 Chevy Suburban
'62 wagon/ ? not a willys  

here is a very unique '47 truck/ '77 J10.

link  http:/www.geocities.com/little47willys/  

just found this willys delivery/wagoneer on ebay.  

  link  http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=220221349777&_trksid=p2759.l1259  

'50 Willys cab/1974 Cherokee frame with 3.9 Cummins diesel, T19 trans and 205 TC for $5000  at http://spokane.craigslist.org/car/664888835.html