What do you think of the Ek-Mana G2 plate? It says it has a DDC pump that can be replaced for a D5. It should look like a custom fit in the o11-mini.
So, general layout idea for the O11D-Mini, mATX 5 slot configuration with a vertical GPU mount. Ek-Mana G2 w D5 pump, to GPU plate, then 120 rad...