[development] Granular Permissions for Administer Content Types

[Shai Gluskin]

Anyone know of a module that adds granual permissions to "administer  
content-types"?

I'm looking for
* create content-type
* administer own content-type

If the module does't aleady exist... I'm wondering about approaches in  
making it. It seems like simply adding a contenttype-user table is the  
key first step. But I don't know a lot about Drupal's access control  
system.

Ideas?

Thanks,

Shai Gluskin