Speakers that image best from corners 12' apart

If you look at this with a strategy in mind
1st take a look at where the speakers are....
You have a side wall,a front wall and wall unit wall coming out beside your speaker.
With each wall we get natural wall gain so you are up in the bass 6 db per wall at about 80 hz
No matter what you try thats a good speaker you will still be way heavy in Mud at that point.
I would suggest you try the Vandersteen X 2 high Pass assesment box and start with lowest setting and work up until you hear a better bass transition and then install that value for the system.
you could also try a pair of pre owned Vandersteen 3A Sigs the Multi enclosure and small baffle less multi enclosure design will seem to disappear better than a box also its 4 inch lighter faster mid range will outperform other speakers in boxes with their slower 6 inch heavier driver and larger baffles trying to do the same midrange task.
Best Johnnyr

Corner placement, good imaging formal room with high WAF, and **well** under $1000?

And a wall unit...

Full-range speakers, most speakers really, that will meet these requirements will be tough to find. And don't worry, you would not find K-Horns for well under $1000 anyway.

Try and find some used Magnepan MC1s. They are wall-mountable; you can hang them with sheetrock screws. That might give you some flexibility with placement and might meet with the wife's approval. When not in use, they lie flat against your wall and you swing them out from the wall when you are ready to listen.

Finsup, interesting recommendation. I saw a pair of these set-up at a dealers in Ohio once, but didn't listen to them (outside of the fact that they were playing music in general).

How is the performance level? Strengths and weaknesses? What type of amplification do you need for these? I am curious.