Hmmn. I don’t really see the problem with using a noun as a verb if it sounds right and has a clear meaning.
Architect is a valid verb ("to architect"), and a sensible extension of the word given that these days an architect needn’t necessarily design buildings.
Your usage "You didn’t architect anything" is fine, but your peeve "I architected this site" is indeed bad form. Architect doesn’t lend itself well to the past tense. It could arguably be "I architectured this site", or preferably "I created this site’s architecture".
There is a big semantic difference between "I created this site’s architecture" and "I created this site’s design", and I can understand why someone who had created the structure of a site but not the physical appearance would not want to say "I designed this site".
In fact, "I structured this site" would be the best alternative.
As an on-topic, "I MODxed this site" seems fine to me.
However, it does seem that a lot of people use this ugly "architected" form, and a lot of people are miffed by it.
For both sides of the coin, see:
http://blogs.msdn.com/ericlippert/archive/2004/10/01/236740.aspx
and
http://pervivere.blogspot.com/2005/09/architect-is-not-verb.html