Dave McC,
I'll see your Tommy Gun and PPsH and raise you one Finnish Suomi!
I've also fired full-auto a drum-fed (ok, so it's actually a "pan") Lewis gun, a drum-fed Soviet light machine gun, and one of those funky .22 rifles by Ilarco(?) that was out in the 1980s.
Coolest drum-fed auto gun I ever fired? An Artillery Luger. Full-auto, you say? That's what we (owner and I) said when it broke as I was firing it!
Luckily, there were only 8 rounds in the magazine at that point, so it didn't get too spectacular.
But, you're absolutely correct about the handling characteristics of drum-fed guns. I'd not be interested in a shotgun so equipped.