Not sure how much coding this would take but it would be awesome.  So the idea would be if you already have a Castle or Keep you could convert the placed Castle/Keep into a custom plot of the same size.  It would just start from dirt then they would need to custom build it from that.  It would be kick ass to have a 31x31 custom plot to play with.
			
			 
 
		 
 
		 
 
		