but check out the docs on single pages. If i had a form I needed to roll out in c5 I would just go ahead and make the single page so i have the theme wrapping and all of that.

Yup me too--it was too much of a hassle for me so I ended up using single pages around my custom form.

Same question: How Include externatl forms in filesystem and place them on pages, Ok use a seperate page, but How do I include them?

The external forms live in the external form block at .../external_forms/forms/ with the correspondending controller at .../external_forms/forms/controllers

If you want to do it via single page, copy the single page to <web_root>/single_pages and the correspondending controller to <web_root>/controllers.

You can add the single page at dashboard->themes and pages->single pages, scroll down and add it by name without .php