To be honest, all Rotom forms work really well with trick sets.
Rotom-Wash is an OU favourite. It has 1 weakness, 5 resistances and 1 immunity, along with good bulk.
Sexy Washing Machine @ Choice Scarf
EVs: 252 Speed, 252 Sp. Atk, 4 HP
- Volt Switch/ Thunderbolt
- Hydro Pump
Choice Scarf is probably the best trick item. While it increases your opponent's speed by 50%, as long as you have a physical/ special wall then you'd be able to take hits. Specs or Band are too much of a gamble, since you could switch with a Pokemon that has a physical/ special moveset. Scarf Trick is especially good for you to ruin a Blissey set, since most people would think you're scouting with Volt Switch.
Will-O-Wisp to render physical attackers useless. Hydro Pump and Volt Switch/ Thunderbolt for STAB.
Rotom-Wash will also work well on your team if you have a Scizor.
Other options would be Rotom(normal), Rotom-Mow, and Rotom-Heat. It'd depend on your team, and what type resistances you needed.
It'd aslo depend on the tier. In NU, Rotom-Fan wouldn't make a half bad trick set with only 2 weaknesses. Rotom-Frost is probably the worst form, especially with a STAB move that only has 70% accuracy w/o its weather type.