I found several boards to be printed in two pieces, but I wanted one printable with two colors, in a single print. Then I added a box to hold the pieces; the letters and numbers, on the box, are meant to be printed in a different color (see photos).

The dimensions are the largest I could fit on my X1 plate, but the model can be easily scaled.

I printed this set to go with the board (scaled down accordingly), by @3DP_Park, which I really like.