Statwise, highest in DEF & SP DEF is Shuckle, but it also has lowest HP & Speed, as mentioned above. Blissey is probably the best special wall, and my opinion for physical wall is skarmory. For the best overall wall, I would go with umbreon, not because it has the best stats, but because I haved used one and can take at least 1/2 the enemy's team down with it.

Stats aren't everything. Yes, they do take a major role in usefullness, but it will be horribly executed if they don't have a good movepool. That's where Umbreon comes in. Not too bad stats, but one of the best movepools Eevee can possibly get, without looking at Vaporeon.

Just because you want an 'OU' team, doesn't mean you're limited to Pokemon strictly of that tier. It's much more effective to design an overlaying strategy and pick Pokemon that excel in the desired role. In the case of my friend's Cradily, her job was to sit there and waste the opponent's PP and fluster them into making mistakes. It is an incredibly sturdy Pokemon.

Umbreon, while cute, I can't see being a great wall. He's sturdy, but he doesn't have any good recovery moves and there's little he can do that can't be reproduced by someone stronger. At risk of sounding hypocritical, I don't like walls that only sit there. Even Cradily has methods of attack, mainly be Mirror Coating Ice Beams that are SE against it. It baits those Ice users and takes them out.

I'm very interested in what ways you utilize Umbreon.

One of my current sets is mainly a counter-attack build. Mostly 252EVs in HP and Sp. Defense, with Wish, Curse, Sub, and Payback. Start with Sub and use Wish to fix what you shaved off from the sub and buff yourself up with Curse. Then start retorting with Payback as you keep yourself healthy with Wish. It's mostly experimental, but I've had it work with my Toxicroak in my Rain Dance team.

I'm glad you mentioned Toxicroak; otherwise, your Umbreon would have an incredible weakness in Toxic Spikes. The idea seems solid, but it seems like against a Sub Focus Puncher you wouldn't be able to accomplish too much. How would you bring it out? What would you put it up against? How would you respond if I, say, brought out an Infernape or Lucario?

Umbreon would mostly be sent in on a defensive foe(unless said spikes are in effect) since mostly they don't have strong power(except the 'Gross). When they switch out, I can safely set up a sub and proceed to use a Wish to heal it off. If they set up, I can start Cursing as well, since Wish will restore my HP. If they attack, I'll still be able to set up a sub(unless she gets clobbered by Machamp) and heal off the damage I took from my moves. Mostly, she's there to scout moves safely. I'm contemplating on switching out Payback for Baton Pass, since Umbreon's mostly for scouting out movesets.

No, keep Payback. Never leave a Pokemon without any offensive moves on your team. It's deadweight if something goes wrong.

You should either go:

Payback
Curse
Wish
Sub

like you have, or:

Baton Pass
Payback
Curse/Sub
Wish

:) Thanks for the tips. I'm always open for improvement and I feel your experience with the "lesser" pokemon is good for me.

I used to think Umbreon good with Baton Pass, Wish, Payback, and Curse, oh wait you did suggest that....

Dusknoir or Blissey, either will provide sound defense, but ultimately Dusknoir can deal some heavy damage giving it the edge in my book.

I don't like Blissey. I don't know why. I've just never had a place for it on any of my teams. There's no denying it's ability to soak up special attacks, but it seems so... there's no class behind it.

I agree, I hate blissey personally, but when you bring up walls it has to be in the discussion :/ I'll find another wall and post it. Just for the sake of eliminating blissey!

Miltank? She's more tanky than a wall, but...

I actually used Miltank with some degrees of success in the 3rd generation. Sadly, I haven't gotten to play much of the 4th since I burned out.

I feel you Goji. I shouldn't have played so much over my senior year of high school. Now in college haven't even turned my ds on.