About spells being dodgeable or not, I am not able to give you a list but I know some spells are classified as somewhat physical. Among those, I think Morgana's snare can be dodged. Should be verified though. (at any rate, I still think dodge>ki cooldown :P)
Oh and I've been thinking about it a little, wouldnt Guardian Angel be better than Mallet as last item? When you are routing the ennemy, maybe Mallet's better but when teams are even I'm pretty sure more resist and 40% more hp pays more.

Thanks for your comments, RaNuD.

I'm still kinda on the fence about Dodge or Health seals. The advantage of Dodge, simply put, is that you take less damage. However, Ki Strike's refresh, according to the tooltip, indicates that it's upon being *hit* that it's refreshed 2 seconds. Also, since spells cannot be dodged (at least to my knowledge), health seals do kind of offer a little more versatility in my mind.

Dodge would definitely be the way to go for pure tankage. Choosing health seals instead does offer a small bit of higher damage (and yes, it's a very small amount that's actually quite irrelevant in the grand scheme of things), at the expense of not necessarily being able to take as much damage.

Runes are still all kind of "meh" in my mind, hehe. Very good point to bring up though.

Your build and explanations are by far the best I've seen on this site for Shen. One question question about runes though. Dont you think dodge seals would be better than health? It means more or less 5% hp versus 5% dodge. While hp is better when facing magic damage, you can dodge some "semi physical" spells, stuns, etc. I'm pretty sur it'd be stronger. Anyways, +1, best guide.