Well, I can see being a delivery driver.  But, for me it was getting in the truck that was the most challenging.  And most will look right over you so they can hire the guy that doesn't need any help!  Let me know what you find as I've been wondering sort of the same thing.

I know a company that has equipped trucks for another driver.  All the truckstops now have handicapped semi parking or they will have it within the next couple years, majority larger ones already have these spots though.  I climb pretty good with my arms, my husband is still an over the road driver so the getting in thing I know I can do, just hadn't really thought the actual 'job' was still possible for me... so I'm exploring some more.

I found this for my state of Tennessee, still trying to make sense of it all though.    http://www.tn.gov/safety/driverlicense/cdlalt.shtml

Found this from federal motor carrier safety administration:
http://www.fmcsa.dot.gov/rules-regulations/administration/fmcsr/fmcsrruletext.aspx?reg=391.43

I've found video's on youtube of paraplegic truck drivers too just by searching that site with various key words. 

I used to haul flatbed, stepdeck mainly, if I get out there again I'll pull a van and team with my husband.  He talked with the company he's signed on with today basically he was told that I need to prove eligible with my home state first what means going through the physical & evaluation similar to what I did to get my regular license after I was able to get around again post injury.