And what do Maggies sound like near a wall......

The out-of-phase backwave will be reinforced by the nearby back wall, and so will cancel out the front wave more effectively than normal. Bass will be weak. The midrange will be colored by the early reflections off the back wall, and imaging (particularly depth) will be compromised.

While you might be able to aggressively treat the backwave and reduce the midrange coloration and imaging problems, I don't know of any way to effectively address the bass problems short of adding a sub.

I would not recommend Maggies for this application.

In fact, there are relatively few speakers that I would recommend for corner placement. What is your ballpark price range?

Duke

I've heard a pair that are placed much farther from the corners but no more than a foot from the back wall. In short, they sound terrible: dull and muffled, with highs and lows severely rolled off. Those speakers do need a lot more room to sound okay.

Duke:
My budget is $1,000. (Used is okay, of course.)
My room layout will also allow narrow (14") floor standing/monitors placed near side walls but 6 feet in from rear walls.

The smaller Maggie models are fairly light weight and easily moved. Is it possible for you to move them to an optimal position when you want to listen and then "store" them when they are not in use?

As stated already I don't think it would be a good idea, mine are 5 feet 6 inches from the rear wall and with any less they do suffer in every way. It took me a couple of months to get them dialed in for my room and listening preferences but now they are "right" and it was worth the tweaking, how ever you do need some room to experiment with. You may want to look into a monitor like the Merlin TSM which works better then most when being placed against the wall- I believe they may be in your price range too- I am just unsure of what you think about monitors.