Fact that there is lots of space is all the more reason to build your own. Cutting, bending, and drilling some bits to make mounts is much easier when there is room to work. Plus you can choose the capabilities of the valve according to your wishes and not just what the manufacturer happens to decide what is most common.
Price is much better doing your own, even as a learning experience.
1 SPOOL 2 SERIES PRINCE STACK VALVE POWER BEYOND