I can't help, but I can express sympathy--I went through exactly the same issue with Montrail after Columbia Sportswear bought them out.
My only suggestion is to keep trying on different models and brands until you find one that fits. You may find a better selection at running shoe stores than at REI. Also, several of the on-line shoe dealers give you free shipping and free return shipping, until you find the pair that fits.
I do suggest that, once you find a shoe that works for you, you buy several pair, before the manufacturer makes more changes.
Also, if you search the internet for the Merrell Radius, you may luck out and find that some dealer still has a pair or two in your size.
May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view--E. Abbey