Everything you ask for is not out of the box. But there are extensions within the MagentoConnect portion of the website that can get you where you need to go. Realize that you are early days and that anything you use as a workaround today, may be available later as out of the box functionality.
There are extensions to
* force login prior to seeing the store, as well as allowing the admin to approve username access.
* filter products and product categories based on customer group
* there is also an extension to filter payment type based on customer group
I don’t know about templating based on customer group.
Price rules based on customer group is out of the box, but I’m not sure if you can price an item specifically from the item maintenance page based on customer group.
You can also have different stores which might allow more fine grained segmentation of end-user audience.
A lot of this relies on customer groups, which are limited at this point. A customer can only belong to one group at a time. So you cannot have overlapping customer group functionality.
I have seen no specific interest expressed by Varien for two distinct versions of the product, rather there will be only one version and it will be flexible enough to work for a large variety of use-cases.