"The Core" Protection Plugin

Yes, this plugin is a protection plugin, although I don't think it has been done before.
Basically, there is a block assigned to what would be called the Core, and when you place it it would create a protection radius (e.g. a default of 5) where no one would be allowed to build in there - but the owner and members of the created region.
To expand the region, you would use the server currency. or an in game item. and then type a command that would remove your items or currency and put them into the core to expand it.
When the core expands, the radius expands by one making the size of the region larger. The bigger the core gets, the more you will have to pay for it. When the core is 10 blocks in diameter, it will cost 100 of the in game currency to expand, yet, when the core is 20 blocks in diameter, it will cost 200 of the in game currency (although the price would be adjustable and there would be a maximum size).

Commands:
/core define | this would turn the block in front of the player to the Core, although the block can't be any random block. This would also only be allowed to be done once.
/core remove | this would remove the core. For the next core defined, the information from the old core will be placed on there (e.g. same sized radius).
/core addowner [player name] | this would add a user to the core who can edit inside of it.
/core addmember [player name] | this would add a user to the core who can use utilities inside of it (e.g. doors). They can't break or place blocks.
/core removeowner [player name] | removes a current owner.
/core removemember [player name] | removes a current player.
/core flag [flag] [allow/deny] | /core flag entry deny | this would add a flag to the region (although only ones they have permission to add - this would be flags in the WorldGuard plugin).
/core info | this shows information about the core stood within (owners, members, flags.)

Permissions would be the 'core.' and then the command name. For example, core.define would allow someone to use the /core define command.

I hope I have explained the basics of the plugin in enough detail to be understood, and if there are any questions then don't hesitate to ask.
I'm no plugin developing expert, but I presume this could use WorldGuard as a dependency (for the flags, adding owners etc.)

Thanks :]