@Bologo's big post
Togetic seems to be fine; dunno if it will work in practice though.
Machoke is outclassed by dotekkotsu (roob's prevo), who boasts sliiiightly lower SpD but higher HP, defense, and attack, which is worth it IMO if you're not using dynamicpunch.
Shelgon and rhydon are good on paper but not in practice - both have nice attack stats and all but skarm can use both as spikes setup fodder and then just ww them away if they get a few too many boosts.
For Machoke, Light Screen and Encore can be important tools that the Roopushin line doesn't have. I took Dotekkotsu into consideration too, but Light Screen is really good for a Bulk Up user since they're not boosting their Special Defense with Bulk Up. Encore means that things trying to set up on him won't be able to. I thought about DynamicPunch too. It's a good option, but I didn't like the idea of being screwed by Burn. However, I'll add it as an option.
And yes, Skarmory can beat Shelgon...but do you seriously believe Skarmory is going to beat Rhydon? Did you forget that Swords Dance is also on the set and that Skarmory will take a shitload from Stone Edge? After a Swords Dance, Stone Edge against the Specially Defense Skarmory which seems to be the most common will do 73.1% - 86.2%. Seriously, if Skarmory comes in while Rhydon uses Swords Dance, Skarmory is completely screwed, because he'll either die, or be complete death fodder for the rest of the match. Don't forget that Rhydon has an equal Attack stat to Garchomp. Even Skarmory will have trouble taking attacks like that.