yees ->

kind of idea is/was a EUROCARD template:

3 + 3 cruvi slots (back + front)
SPACE for "brain" in the middle
fits some existing enclosure for eurocards
"some" connector front - RJ45 gBe ?
power connector back

the brain could be 4x5 module or soldered down ECP5 also or some other FPGA

How about designing a carrierboard with this module
https://shop.trenz-electronic.de/de/TE0713-02-200-2C-FPGA-Modul-mit-Xilinx-Artix-7-XC7A200T-2FBG484C-4-x-5-cm-1-GByte-DDR3L?c=457

and some cruvi interfaces as demo?

Ed