The extended Sprinter afford the best of both worlds in the compromise arena of which LBD spoke. The revenue potential between hauling two skids and three skids is minimal. You may get more loads hauling three skids, but they rarely pay more. Plus, it's quite a tradeoff when you have three skids on board and no place to sleep for three nights on a Friday pickup for Monday delivery going 500 miles. Been there, did that for years, so the ability to sleep while loaded is paramount for me.
I have a 30" bunk and another 30" for "living space", and then 108 for cargo where I can comfortably carry two skids. With the new Sprinters, the longest ones, you can actually have a bunk and still have room for three skids. You won't have much room for anything other than the bunk, won't have any "living space", but it can be done.
In expediting, most loads ate two skids or less, or more than four skids. There are certainly some three-skid loads, but they are a small percentage. Those that I know who can haul three skids rarely do. Another factor with three skids in a Sprinter is, often the weight of the third skid is enough to put the vehicle overweight, so even if you could fit it, you can't haul it, anyway.
There are absolutely plenty of three skid loads that a Sprinter can haul, but for me, that ability doesn't justify not having a permanent bunk and a place to sleep. I may miss out on a few loads because of it, but I rarely miss out on getting a load completely because of it. More likely, there's a 3-skid load sitting there to be shipped, and I'll get the 2-skid load sitting next to it instead.
Regardless of what you do with it insofar as outfitting it, when all is said and done, when it comes to a cargo van or Sprinter, the bigger the better.