all wheel drive van

I have been a building contractor for 30 years now and have owned mostly Ford vans for work. And living in the northeast where the winter months can (and usually do) dump alot of snow here. No matter where we worked when they predicted snow i would prepare myself, crew and customers that if it snows we won't be on the job. And every year on every snow storm i would at some point think to myself why cant they build a van with four wheel drive, I know they do, if you are referring to after market 4x4 systems thats fine for some but not me not a ideal solution. And I know Gmc had a mini van with all wheel drive and even a full size model as well  and dont even think they still offer it however I'm not a Gmc or Chevy guy.  I have always wonder'd why Ford never toy'd with the idea especially now that all most every car company offers a all wheel drive option on so many cars. After all we do have the number 1 selling van for 34 years. I reed a article a while back that said based on  vehicle registrations Ford has over 75% of the van market. If this is true I wonder why a company like nissan would even waste there time introducing a van to share a 25% share of a market. Not to mention they are ugly and I know you will never find me behind the wheel of one...
art h 02/02/2014
Back in the 70's Ford did have a 4 wheel drive van. It was not aftermarket. I like the idea.