Step 1: establish your budget.
I've got a 100% duty cycle Viair 12v compressor with a 2 1/2 gallon tank mounted on my other truck. It is pretty slow for filling big tires, but it will never run out of air. I want to say that was around $250?
One of my friends runs a York engine driven compressor. He can run an impact gun off of it without a tank, fills up tires fast. He sourced the compressor from the junkyard and made the brackets himself, so he's only into it for ~$100, kits are available for around $500. Oasis makes an electric powered (basically uses a winch motor) York setup that is just as fast (cfm) as the engine driven one, but you can mount it anywhere. Make no mistake about it, they are spendy: The Most Powerful DC Air Compressors in the World
Another friend uses a powertank, it will fill a tire faster than the rest, but like you said, it has to be refilled. I like to borrow it, but I don't like that I can only air up all 4 tires 2 times on a fill. If airing up wuick is your #1 goal, you can even get high flow valve stems and air up in a few seconds!
As much as I'd prefer a substantial air system on the van, I just don't find myself airing down often enough to offset a $800+ system. I think the Viair 440p would be a reasonable compromise for occasional use.