I haven't called to verify but someone over at Glocktalk is reporting that MRI has 10" DE barrels available again.  Posted the following:

FYI, Magnum Research now has a limited supply of 10 inch barrels available. They are not on the website but you can call Magnum Research and order them over the phone. Call 218.746.3459 and leave a message for Matt or Jeff to call you back. They have 44 magnum, 50 action express, and 429DE 10” barrels available. I bought a 50 AE ($827) and 429DE ($799) and have been putting them through their paces over the last few weeks. They are both drop in fits for my US made Mark XIX.

I'm trying to remember, but it seems like they were asking around $600 when they were available a couple years ago.  But that's when you could get 6" barrels for $400 or sometimes a bit less.  Got to love inflation.

ETA: the same poster (same screen name anyway) posted some additional info on AMT Guns Forum, including this tidbit:

They offer a threading service but it requires the barrel to be cut back to 7”, so I passed. You have to specify the thread pitch. The cost is $225 extra for the threaded version.

Having chopped & threaded a 10" .44 barrel back in 2009, I can attest that the DE isn't an ideal suppressor host.  However, it's still an interesting one to shoot.  I wonder if we will be seeing a few more DE suppressor videos in the near future.

I have an interesting idea of how to accomplish this, but I don't have the fabrication equipment to build it. Maybe one of these days...

Good find.

Looks like both are for a MK-VII