Yep, Rugged Obsidian 45 as said above - good balance of price vs performance, and rated as one of the quieter big bore pistol suppressors. Of course you could look at a dedicated SMG can (fixed mount, and generally larger than pistol cans) if you don't want to also use this on a semi-auto pistol, but I'm not as familiar with SMG suppressor options these days so I'll leave it at that.
If you have one of those lever guns shortened at 16" (or even shorter as an SBR - respect!) and want a short compact suppressor, the Obsidian 45 is modular and can be used in a short configuration. It's definitely a bit louder that way though.
One comment for 45/70 use though - Rugged doesn't say in their literature, but having designed and machined a number of F1 cans, and looking at how this one is made, I'd be a little worried about using it with full house 1895 Marlin loads. My guess is that rating is intended for Trapdoor level ammo, which most factory loads are. A few places like Buffalo Bore sell the hotter loads intended only for strong lever guns and Ruger #1s, so use caution if you want to suppress those; they put out a lot more gas volume and pressure at the muzzle.
I think that Fly45 is a great option too, if it's in your budget.