Mounting a mosaic modularly I have this LEGO mosaic consisting out of 3 by 3 baseplates (32x32):

As it takes up too much space lying flat, I would like to mount it vertically or near vertically, slightly leaning backwards, like on an easel.
I'm looking for a solution that is modular, i.e. that I can easily take apart in smaller parts so I can put it in luggage for travelling and that is also as easy as possible to reassemble.
Also, I'd prefer a purist lego only solution, avoiding gluing if possible.
Any ideas?
I can suggest using a base MILS module (BTM-1 on the picture below), basically an extra layer including some Technic Bricks around the edge for connectivity between modules as well as some plates on top of existing baseplate. Yes, it is going to be bulkier and heavier, but at the same time much more sturdy and easy to assemble and take apart for travelling.
This also has an added benefit of making your surface 3D (BTM-2) if needed.

UPDATE
LEGO has now produced their own MILS-like elements used as a base layer for mosaic sets as well - Technic, Brick 16 x 16 x 1 1/3 with Holes (65803)