I have been seeing some around lately, really roomy, by no means small. These American versions are larger than my current van, a GMC 2500. About 2' longer, and 2~3' higher, no more drive-thru lunch for someone driving one.
There are three wheelbases and two heights for the Sprinter. Only the longest wheelbase with the high roof is as large as you describe.
Leaving the vans... the small cabovers have smaller diesels also. Ford LCF, Isuzu NPR, GM W-series, and Mitsubishi Fuso come to mind.
