Depends on the paint... some jars, I'll put a decent amount on the lid, if the lid's white and I can read the color. Then seeing it from the top's no problem. For my Vallejo line, I have to go by a chart and shake the bottles, and well it's a pain too... the Model Air line is small compared to their regular line, but still, lotta damn bottles. Vallejo's pretty goof proof for spills, so I'm lucky there.
Anyway, again, it depends. I only box up stuff that's relatively nasty, and it stays ventilated. I've just accepted that hunting through the nasty Floquil, etc is part of getting ready to work. For other colors, I have them sitting out, relatively in the open. In the past, I've used boxes, but kinda got to where you are, it's a pain if you need to find something on the fly.
I don't know of any perfect solution, maybe a lucky find of a spice rack, mount it to the wall so you can see the botttles from the side? I've really never even seen a good 'purpose built' paint stand for such.
Good luck, if anyone's got any ingenious solutions, I'd love to hear about them...