I use this a lot in practice. Basically, instead of your lever arm just resting on the shoulder, pummel it through for a half nelson and put the choke in with the other.
I find that this is much harder for the guy to roll out of, and only takes a bit of work to get in. I'm aware that the extra reinforcement that the nelson gives you is not always necessary if you've got a nice choke it, but i find that it helps you in the hand fight.
Anyone else use this? Just curious.