I have used 2 aftermarket columns on my current build, the first was a Ebay purchase and was a full length column probably more what you are looking for, I ended up selling it since I decided to go with a floor shift but if you click on the link you can see what I had to do to make it work. It involved making a special size lower mount locking ring. For the Flaming River column I'm using, I welded on the OEM mounting lugs for factory under dash mounting. Either way To get something to work your going to probably get into some fabrication.
http://www.forabodiesonly.com/mopar/showthread.php?t=176692