Tim Rowledge wrote:

	A quick google finds a proposal page pretty quickly, along with some
	pages describing how to pronounce it all. But damn it, if they can have
	Tengwar, I want to see Marain included
	(http://homepages.compuserve.de/Mostral/artikel/marain.html) !
	
The final sentence on that (badly spelled) page is
    "So humans can use Marain to confuse their fellows, too."

As described in that page, Marain is open-ended.  It is explicitly
stated that you could have a grid a million on a side, which is to
say 2**(10**12) "characters".  This seems to disqualify it for
inclusion in a 31-bit (10646) or 21-bit (Unicode) code.

On the other hand, Unicode _could_ be mapped into Marain.

Either way, write up a proposal and see what happens.