With the rarity of those things I think I'll be painting a can of Danish butter cookies and gluing it on to the factory mag!
I wanted to suggest that,
but I didn't, so you couldn't say
I was guessing your mind
The 10/22 drum is something very expensive
and a lot of people are complaining of its reliability.
In addition to that, I think it wouldn't sit at the correct angle
or at the correct distance from the gun
(in the PPSh, the round part of the drum is very close to the gun,
the 10/22 is too far).
Making your project with a can attached
to the existing 10 rnds mag would make you solve
all these differences.
Just walk the aisles of your food favourite store and ideas will come.