Interesting idea. http://www.xlhybrids.com I've seen a few in GMC 2500 Savana cargo vans around here. Although, the one driver I talked to - I had him show me the dash. He was averaging 15.5 mpg with the hybrid, and it was the same van as mine - 2012, 2500 with the 4.8L . He said you can feel it in town, and on hills on the express way.