Peter, that's a good list! Very similar to the requirements I was searching for. I guess there is no perfect vehicle but some are definately better than others.
There's no perfect vehicle, but there is a perfect vehicle for you. (and me, since you agree with my list) There's just not one perfect vehicle that suits everybody.
I wore out three Asstros and two E250s before I finally found the perfect vehicle for landscape photography. : ) It just wasn't available back then. But it is now. It's a European LCV "Light Commercial Vehicle" made by Mercedes Benz. The Sprinter carries Dodge badging, but it's a Merc, through and through.
You get a lovely little five-hole diesel and a six-speed tranny that combine to deliver great performance and nearly 30 miles per USG, if you treat it really nicely. It has really long legs. I can easily go a thousand kilometers (600 miles) on a tank.
It has quite high ground clearance and the view out the windshield is without peer, and that's the point, isn't it?
Maybe best feauture of all, you can stand up and walk around inside. Six feet of headroom. Imagine!
You can see it in this thread:http://www.luminous-landscape.com/forum/index.php?topic=73877.0
and you can learn all about them here:http://sprinter-source.com/forum/index.php
I do use an Engle cooler in my van
On my list. So far, I just use a very well insulated ice box, but I can see the need. Being able to make ice would be a good thing, especially on those summer evenings in the desert.
Van is also not too secure. I had wanted something with a real trunk then decided I could just make a box that's going to be really hard to get into and mount that in the van. When I'm hiking, I store stuff in the "lock box". Safe from smash and grabbers but not going to stop a serious crook with time at the remote locations I'm usually at..
Always a problem. I hate even leaving it for a minute, especially in urban areas. I trust that the kind of people that frequent the remote sites are honest. Elsewhere, there's nothing much you can do, other than get a really big, loud dog. Fortunately, people seem to ignore me. I've slept in some pretty weird places in cities and it seems you're just invisible.
I just want to get in go on the cheap.
Used Sprinters are out there. Fifteen large would get you a reliable ride and you'd never pay for a motel again. They are a bit of a princess, though. The older ones are better, but the current models are loaded with drivetrain management computers, anti-pollution junk and tons of stuff nobody can fix unless they have the proper diagnostic tools. Something to think about when you're parked somewhere miles from anywhere else.
I'm off to the desert with two new cameras and two new lenses in about a month. Can't wait.