5.1 A/B switch - XLR - where?

Can anyone recommend a (sonically transparent) 5.1 A/B switch with XLR connects?

To elaborate, I wish an A/B switch with two sets of (5.1) inputs & one set of (5.1) outputs - utilizing XLR/balanced connects. I can't seem to find anything suitable via the obvious search methods.
assemble multiple of 2ch ABs
The only ones I know of are out of production:

Perhaps you can find one.
Shalco Switch

These guys can make a custom switch for you then buy some XLR panel jacks and make your own. You'd need a 12 pole switch with 2 positions.

Best of luck

Wow, so much more complicated than I anticipated ...
Thanks for the suggestions folks!

More than you need and probably more than you want to pay, however this Model 7299 Eight-Channel XLR Audio A/B/C Switch looks like it will definitely do what you are asking for, and have capability for up to 7.1 A/B/C switching.
Thanks Tls49 - it's actually cheaper than the $5k I've seen quoted for the now defunct EMM Switchman's - but still more than I wanted to pay...
Are RCA/Unbalanced switches any more available/affordable?
Yes. I prefer the Zektors but they, too, are only available used. There are others, though.

Salmonsc, the company that makes the switcher in my previous post also does custom work. There are a few options to Begin the Design Process for your Custom Data Network Switch. They may be able to give you a price by phone for a 6-Channel XLR Audio A/B Switch.