No offense but this indicates that you have not played as many games in League yet. If you do, then you would know that there is no "doesn't work at all" builds, they are just not suited for most situations. For a regular game where there are AD and AP carries on your team. There is a support and there is a tank, the need for an AS Irelia would be low and it would be better to have an offtank dps.
As I stated in my introduction that I am not against regular offtank build. Please refer to my previous response to another reply for more details.
Why do so many people love SivHD's jungle Annie, Mundo, atmogs Twisted Fate, and etc.? Because they find one game where the build is perfect, and they realize that it works - just not in many other games.
Please understand that there is no one fixed way to play a champion in League of Legends, which is one of the reasons we love the game so much.

Indeed you rarely see an Irelia with full AD or full AS. As I stated in introduction, I am not against the regular off tank build. I personally build Irelia off tank more often than this build for situation needs.
I don't know if you follow Siv HD, but this build is trying to bring out another potential of Irelia just as Siv would suggest strange builds for champs (like atmogs TF, AP Poppy, Jungle Annie etc.). They work in certain circumstances but maybe not in most games (but that doesn't mean the build doesn't work, just not for the time).
I thank you for your acknowledgement of "good" for my guide.

Thank you for your advices, I have understood what I really want to bring out of this guide. This guide has been modified. Please read my introduction then consider the build.

Bad guide - building offtank as an ad carry just doesnt work at all!!!

Bad guide - building offtank as an ad carry just doesnt work at all!!!

Ok this is a good guide, but, the item selection is really wierd, even if your going AD, your building more Teemo than Irelia to her true potential. Irelia was meant for an off tank with damage in either AP (never seen that) and critically striking. Never seen a Irelia all AD and attack speed.

Fail dude,fail,I see you are trying to heal yourself,but there is few reasons.
- Irelia is not a carry-play a month with this build and you will realize that she is a better offtank(or even tank).
-Masteries.You've gone heavy AD carry which I would not recommend.Better take armor penetration and all other on defense.Or you also can have 9/21/0.
-Spells-better take Ghost and Ignite.
-Runes-I can guess you know that you can only have 3 quintessences,right?
-Your guide is kinda short.