Huzzah! So some progress.
So since my last update, I've pretty much decided to go with Chris's method of laser etching (if it proves possible/plausible) so that means I need a 3D model of all of the pieces with their major detail, such as borders and large grooves, and a file with all of the designs to be engraved on them. Once the pieces are engraved I'll be sending it to someone that is set up for casting/molding, preferably someone with a vacuum chamber for maximum detail/minimum bubbles. Whoever is molding/casting it will probably be the one setting prices and such for any runs, since they'll be the one doing all of that work.
In order to make this project as easy as possible for the other people I'm handing parts off to, I'm trying to design the 3d print as a sprue, so as you can see on the picture of the bottom, I've added a structure for the pieces to be attached to. This sprue has to do 2 functions though, 1 is it must keep all of the detail pieces together and aligned and with all of the faces to be printed on in relatively the same plane (If I have something that is like 1cm higher then another the laser won't focus properly, so I'm trying to keep all faces withing a few millimeters of each other). It also has to keep all of the pieces together for the purposes of molding and casting, without impeding that process. I'm TRYING to keep all of the detail pieces in one chunk and the "peg" pieces in one, in order to keep the manhandling to a minimum, but it might be easier to do 2 or 3 chunks each? I'm just thinking now about the problems of molding a then flat piece with not much support on the inside, I can certainly see it sagging in the middle.
Currently I have a sort of lattice underneath the detail pieces, this is to both raise them up to allow for the larger curve the corner pieces will have, and to keep the entire model as flat as possible when engraving. I built it to be able to be broken off before casting, but I'm worried it won't make it through the mail to me/the engraver. The little square poking off of it has an X on it that I would mark with a pen for clarity, it's my idea of a registration key, I would line up the engraving file to at least 2 of these things in order to align everything. Also the peg's apparently broke apart while he was washing off the support material, so I'll have to give them some extra support, which isn't hard.
So the final kits with look similar to these. They would be big sprues of resin or what not, that you would break apart, clean up and attach to an Eastsheen 4x4x4 which are about $15-$20. The pegs will be filled in prior to casting, so they'll probably be more solid, but that's up to the caster.