Here's something that can only work in pre-BW:
Lead with Smeargle. Max speed. Focus sash.
Obviously any taunt lead or anti-lead will destroy you. This can only be set up against things like swampert; basically slower pokemon that set up hazards.
The idea is to use Spider Web or something of the like first turn when a metagross is using SR. Although, most players would go for Meteor Mash versus a smeargle.
Anyways, the foe is now trapped, and they just set up rocks. Smeargle then proceeds to Encore, thus disabling their lead altogether for the next 5-8 turns. As for the last move, well, there are a few options, Spore and Ingrain. It's very situational, Spore can help with leads that will completely mess you up anyways, things like TrickScarf Jirachi. Ingrain obviously gives recovery and prevents phazing, but you'll find that if you can pull this strategy off, Cradily or Octillery will be more than good enough to sweep. Here's where the magic happens:
Baton Pass into one of the few Pokemon that can learn Trick/Switcheroo and and Baton Pass. I suggest Drifblim, as it can outspeed a lot of things when max speed with a Choice Scarf, and even more things with an Unburden boost after you Trick your foe into the scarf. The foe is now at your mercy. They cannot switch, they cannot attack, they can't do anything. Do what you want with Drifblim. You can set up a super bulky Substitute and Stockpile up, or just Baton Pass to something like Gorebyss to set up Amnesia/Iron Defense/Aqua Ring.
After you have your defenses set up, proceed to Baton Pass to something like Ninjask or Gliscor that can set up Speed and Attack for a Physically-oriented Baton Pass receiver. Or, if you prefer to pass to a Specially-Oriented receiver, Minun/Plusle and Ambipom/Aipom are available for having the handy ability to be able to Baton Pass Agility and Nasty Plot.
Time for the sweep. Make sure you have a Substitute for blocking status and critical hits up, because right about now your foe is about to Struggle. Literally any Pokemon can pull this off. I've done it before with Pichu and Chimchar.
Well, good luck, and have fun.