Weak to none of those types:
Hitmontop
Item: Leftovers
Ab: Technician
EVs: 252 Sp. Def, 200 HP, 56 Atk
Nature: Careful
Bulk Up
Bullet Punch
Mach Punch
Rapid Spin/ Fake Out (depending on the rest of your team)
Hitmonchan
Item: Leftovers
Ab: Iron Fist
EVs: 200 Sp. Def, 200 Atk, 108 Speed
Nature: Careful
Bulk Up
Mach Punch
Bullet Punch
Ice Punch/ Rapid Spin
Problem is that that Hitmontop and Hitmonchan have no reliable forms of recovery outside of Rest, and both have a mediocre Defence.
Rotom
Item: Leftovers
Ab: Levitate
EVs: 252 Sp. Def, 252 HP, 4 Speed
Nature: Calm
Pain Split
Will-O-Wisp
Thunderbolt
Shadow Ball
I would suggest Rotom-Wash (best Rotom typing), but it's OU, and Rotom-Heat is weak to Rock & Water. Rotom also has no reliable form of recovery, since Pain Split is situational.
Mismagius
Item: Leftovers
Ab: Levitate
EVs: 252 Sp. Def, 200 HP, 56 Sp. Atk/ Speed
Nature: Calm
Calm Mind
Shadow Ball
Pain Split
Hidden Power Fighting
Again, situational recovery.
Cofagrigus
Item: Leftovers
Ab: Mummy
EVs: 252 HP, 200 Sp. Def, 56 Def
Nature: Calm
Calm Mind
Will-O-Wisp/ Haze
Shadow Ball
Hidden Power Fighting
^ The mother of all walls. I know Cofagrigus has a base 145 Def, but a 105 Sp. Def isn't shabby.
Dusknoir
Item: Leftovers
Ab: Pressure
EVs: 252 Sp. Def, 252 HP, 4 Def
Nature: Calm
Shadow Sneak
Will-O-Wisp
Pain Split
Shadow Punch/ Seismic Toss
Spiritomb
Item: Leftovers
Ab: Pressure
EVs: 252 HP, 252 Sp. Def, 4 Def
Nature: Relaxed/ Impish
Will-O-Wisp
Pain Split
Shadow Sneak
Foul Play
Other Pokemon that are hit by those moves neutrally (which come to mind) are Kingdra, Muk, and Ampharos, though neither would make an especially good wall.
Other options
Milotic
Item: Leftovers
Ab: Marvel Scale
EVs: 252 Sp. Def, 252 Def or HP, 4 Speed or Sp. Atk
Nature: Calm
Scald
Recover
Haze
Toxic/ Dragon Tail
Slowking
Item: Leftovers
Ab: Regenerator
EVs:128 Sp. Def, 128 Def, 252 HP
Nature: Calm
Scald
Slack Off
Fire Blast
Thunder Wave/ Psychic
Umbreon
Item: Leftovers
Ab: Synchronise
EVs: 252 HP, 4 Def, 252 Sp. Def
Nature: Careful
Wish
Heal Bell/ Yawn
Foul Play
Protect
Bronzong
Item: Leftovers/ Light Clay
Ab: Levitate
EVs: 128 Def, 252 Sp. Def, 128 HP
Nature: Relaxed/ Calm
Reflect
Light Screen
Hypnosis/ Stealth Rock
Gyro Ball
Scrafty
Item: Leftovers
Ab: Shed Skin
EVs: 252 HP, 4 Atk, 252 Sp. Def
Nature: Careful
Bulk Up
Drain Punch
Crunch
Rest
My favourite set for Scrafty, but Shed Skin isn't reliable.. in any case, this set sees a tank Scrafty that will be able to pack a punch with some set up.
Those are my ideas for a special wall. In any case, Ghost, Electric, Poison and Fighting are the only types that are hit by those moves neutrally. I might have missed some dual types that get neutral damage...