[Feature Request] Limit region to subset of templates

From a client's ease-of-use standpoint, I think it'd be great to be able to limit content regions to specific content templates.

I'm building a portfolio site for an agency and one of their requirements is to have relatively free-form project pages, so that each project/case study can have a tailor-made feel. That's pretty easy to do by just making a bunch of different templates for each major content type (like video, image gallery, testimonial, etc) and letting them choose a different template for each content block.

Because the internal nomenclature is "Projects" though, each of the content block templates are listed far down the template selection dropdown, and they're presented with a bunch of different options before they get to the Ps. Basically, my feature request is to be able to limit what's shown in the drop down to choose templates.

For the projects section I really like the control that perch_content_create() gives me, by letting me dictate which template to use, where it should appear in the page hierarchy, and how its editing interface should present. Once everything is set up correctly, I think it's a great trade-off (slightly more initial dev effort) to give my client ease and assurance that the content they're about to enter will appear correctly the first time.

Essentially what I'm asking for is an expanded 'template' key in perch_content_create(). The project page type is set up like this:

  perch_content_create('Header', array('template' => 'projects/header.html')); // Constant page features

  perch_content('Header');
  perch_content('Content Block 1');
  …
  perch_content('Content Block 5');

Each Content Block n has to have its template selected (which lives in content/projects/*) manually. What I'd love to be able to do is the following:

  perch_content_create('Content Block 1', array('templates' => 'projects/*'));
  …
  perch_content_create('Content Block 5', array('templates' => 'projects/*'));

Then as they add each content block, the only templates they're able to choose are templates designed to work on that page.

Anyway, just a thought. Loving 24ways this year btw :)

Thanks much,
MG