I’m about to paint my stairwells which have walls and celings I cannot possibly reach. I have played with various combinations of ladders and planks and have not come up with scaffolding I feel comfortable standing on. For instance, in one set-up the ladder does not fully unfold and lock, and I can’t figure out how to use a straight (vs. A shaped) ladder in a way that seems secure. Does anyone either have advice or a web site that might give me an idea as to how to set this up safely?
Don’t jerry-rig some scaffolding. Go get the right ladder. My neighbor didn’t, now he’s dead. Please get the right ladder. Here’s an extra push: http://www.darwinawards.com/
Don’t do it, bro. You’ll get hurt. 
I have two ladders which I use for stairwells. One is a Little Giant which isn’t made any more so I can’t link a picture of it, and the other is a Gorilla ladder very similar to the Little Giant 1A model 22. Along with them, I use several telescoping poles, and some pads with wheels on the edges to handle high walls and ceilings without actually getting within 2 feet of the surface being painted. Falling sucks, but the sudden deceleration sucks even more.
You can rent scaffolding at home depot.
First, you are absolutely right about having the right ladder. They do not make ladders for staircases. You can rent scaffolding from Home Depot, but it does not fit in the confined space of a staircase. Although they look good on TV the articulated ladders do not really do the job. I do use telescoping poles, but need to raise myself up nonetheless.
Your best bet is to either rent scaffolding or hire somebody to paint that section.
Rigged up scaffolding is a serious hazard and proper scaffolds / ladders will cost too much for a one time job.
John F
Bolding mine.
Beg to differ. Part of the beauty of a Little Giant, and those styled similarly is that they afford a safe, firm climbing means on stairs. In addition to the A to straight conversion feature is the ability to extend either side of the A frame independent of the other, making them ideal for stair work. Don’t confuse a Little Giant with the four section folding ladders-that’s a different beast entirely.
Forget using ladders and/or scaffolding. Just get an extension pole (or series of extension poles) for your brush and roller.
Another solution: 55-gallon drum of paint, toss in hand grenade, run. 
I can barely cut in edges with a regular brush, how the heck could I do it with my brush on a pole?
Practice, practice, practice. Ne shitteth vous pas. Obviously build up your cutting skills on something that is of no importance before you move inside your home.
In difficult circumstances (e.g. cutting French window panes at 20 paces) you may have to get a buddy to hold a mask in place.
Once you get the hang of it, the only frustrating part is how slowly it goes, particularly when you have to dissasemble the extensions to get your brush or roller down for re-loading with paint.
Or a small trebuchet and paint filled balloons.
Or one of these: http://www.flying-contraptions.com/history.html
Jury rigged scaffolding
At first reading this looked like the headline of a news story pertaining to a trial in which all semblance of impartiality had been lost.
As a last resort, some pad painters with edge wheels work nicely on the end of a painting pole. I’d prefer to use them over precarious climbing arrangements. Don’t overload the pad with paint and make sure dropcloths are placed.
I don’t know why you think that the Little Giant isn’t made any more. They run infomercials all the time on late night TV.
I have both the Little Giant model 22, and a Gorilla in a smaller size. The Little Giant is able to handle a heavier load, me, better than the Gorilla. if you’re not overweight, the Gorilla is a good ladder.
Either one will work fine on stairs.
Now I feel as if I should hang my head in shame for having built my own scaffolding expressly for this purpose. I built it out of 2x4s, plywood, and big carriage bolts. It was sturdy enough for two guys to work on.
Of course, we were ripping out the ceiling at the time, so the extension trick wouldn’t have worked.
It has been awhile, and it looks like I need to add a new coat of paint. I plan on trying out the long pole method this time around. That scaffolding was an incredible pain in the butt to set up.
I know that they’re still in business. Perhaps the way I worded it confused you-the specific model of ladder that I have isn’t shown on their website, leading me to conclude that that model isn’t made any more.