Whoa, your team rocks!! OK here's my ideas.
Rapidash@Leftovers
(I'd go with Fire Blast) Fire Blast
Sleep Talk
Rest
Horn Drill
I'm thinking Charm for forcing switching, Fire Blast for Skarmory and Steelix, Hypnosis for fun, Reflect for Pseudo-passing, your choice.
Lapras@Leftovers
Sleep Talk
Rest
Horn Drill
Ice Beam (Keep Ice Beam)
I think this was one of the old standard sets.
Tauros@Leftovers
Sleep Talk
Rest
Horn Drill
Fissure
a OHKO team wouldn't be complete without it.
Nidoking@Scope Lens
Horn Drill (Horn Drill rocks!)
Counter
Earthquake
Thunderbolt / Lovely Kiss
Dragonite@MiracleBerry
Thunder Wave
Horn Drill
Agility
Ice Beam (NO WRAP, IT STINKS!)
From R/B/Y, it works. Possibly wrap to trap them.
Machamp@Quick Claw
Cross Chop
Earthquake
Rock Slide
Fissure
I really like your team. It didn't need any help, but it's nice to get some advice.