Switchable templates over the back-end with template showcase?

With New Blog Templates and Pro Sites network activated on WP Multisite

Front-end -> All the list of demo sites are viewable in the proper template showcase page and can be selected to use creating a new site directly via the front-end as a template in order to duplicate the exact same content, settings and etc.

Back-end -> WP Dashboard >> Appearance >> Themes --> All selected templates, [theme enabled in the network], from "/wp-content/themes" are listed in this section.

Why this approach and why I wish to achieve this method?
Because I have, say, Template name #1 is normally displayed in the Themes section but I created the subsites based upon the layout of template #1 which are significantly different in their appearances and everything else called #1.1, #1.2, and #1.3. All these 3 subsites + templates (based upon the template #1) are displayed on the front-end in the template showcase section but not at the back-end because they're not the main template model (sorry for any confusion, please ask if you don't get it).

Why not making the #1.1, #1.2, and #1.3 as their own templates with their own separate themes folders under /wp-content/themes/#1.1 and so forth?
It's the last solution I can think of to sort this issue at the moment, but I think they're redundant as their structure are all the same as the #1 and will consume too much physical resources. I'm not talking about 3-4 subsites but what if there are 200 subsites based upon a few template models, do I need to creating all the 200 subdirectory templates in order to have them available for selection over the back-end?

1. Is there any workaround to have all the templates listed via the front-end populated all of them in the back-end either in the same area of the old template section or have their new own section without applying those methods above as I try to avoid using them?

2. Is there any plugin available out there to wipe off the subsite content, media, and else to a clean state by selection (wipe off the whole site, delete only the pages and posts, and etc) per blog_id designed and secured enough for multisite in preparing for the template switching? Any other new better approach?