All right so the tub has slowly been getting worse. So I decide to snake it not knowing there was a drum trap in the first place.

The snake pulls out the usual suspects, hair, grime, etc...

The tub now refuses to drain at all... I finally find the drum trap and go through it, a little (and I mean just a little) bit of left over grout from the tile guy who redid the bathroom (damn him), but not huge pieces that I would consider a big issue. But all in all the drum was clean.

So I try to snake past the drum and have come to a point where the snake will not go any further. Is it possible there is a P trap after the drum that the snake can't get around? Or have I hit the mother lode of all blockages?

I try to snake past the drum and have come to a point where the snake will not go any further.

First of all you better take a look at how drum traps are made, see image).
Do you see why you couldn't get past the trap?

Is it possible there is a P trap after the drum that the snake can't get around? Nope! Once you remove the cover and snake the top pipe you can rub-a-dub safe in the knowledge that when you pull dda plug it's going to drain. Good luck, Tom