Question: Is there some way to tell who has created which tags, and when? If a method doesn't exist I would petition SO to add this, as I would very much enjoy seeing tags I created being used by other people. 

SO must track creator meta-data on tags since a badge is awarded for creating a tag used by 50+ questions (taxidermist).

Answer: 
There is nothing in your user page that will help with this, but following the chain below you might be able to figure out if you asked the first question with a specific tag. However, I'm not sure how retagging and/or deleted questions are treated in relation to the taxonomist badge.

`Tag -> sort by newest -> last page -> question on the bottom`, should be the earliest question asked with that tag, but still not guaranteed that that question or that user created the tag.
I have a list of which users created which tags, but Jeff has said he doesn't think any good can come from disclosing this information. I may be persuaded to help you if it's regarding a specific tag or user, but I won't help you if the tag has less than 50 occurrences. 

In the general case nothing from SO will help you in finding such information, and you'll have to compile it on your own.