I could create a blog with my own URL and branding with selected Steemit posts
Yep
Could those be from any user?
Yep
Will it allow for comments? I guess it could require Steemit signup to comment, but that would bring in new users
This will be a bit further down the line, but it's absolutely something we'd like to add in.
I'm glad you're seeing what we see - some intriguing possibilities :)