Those are CR Lawrence sunroofs that Discount Van sells. CR Lawrence and Donmar are the only flush-fitting aftermarket sunroof makers I am aware of these days.
I installed a CR Lawrence style sunroof into my little commuter car a few months ago. BTW,
The traditional 'crank up RV' sunroofs don't look that good, but are hard to beat for functionality and serviceability, with fan options.
If you want to go with the automotive flush-mount type, I did a lot of research into getting it right before I bought mine, here's some tips:
Check the CR Lawrence fitment table first, use the recommended part number for your van to shop around.
http://www.crlaurence.com/datasheets/pd ... Guides.pdf
Definitely choose the 92% tinted option, even at 92%, it could be darker for my taste, on a sunny day. It still lets in most of the visible light, blocks 92% of only the UV spectrum. Clear would be silly, unless you live someplace gray like Seattle WA or Rochester NY.
Some roof lines are more curved or more flat than others, some roof lines have a more pronounced compound curve (curved lengthwise AND crosswise at the same time). Choose the wrong one 9like I almost did) getting the wrong curve, and (so I'm told) your sunroof will leak, no matter how good the instal.
They instal pretty easy, you can do it in an afternoon unless you have a headliner to deal with. After careful layout and centering of the supplied pattern-paper template, I cut the hole in my roof with a sawzall. Pneumatic or electric power shears would have been better, if I had a set. I would not however, use an abrasive cut-off wheel, or tin snips, as you'd just make a mess. Screwing in the extruded aluminum trim (from the inside), draws the outside flange tight, squeezing out the supplied putty for a nice seal. If your van's roof is stamped with those corrugations, I think CR Lawrence offers some foam spacers to fill the low gaps, they might even come with the kit.
I hope that helps