From a commercial point of view I would rather add the mods to the TC-7520, instead of to the Caiman. The TC-7520 is put together on a production line, which saves cost, and would therefore only add a small proportion to the overal price I reckon.

The Caiman is tedious to build due to the various mods that need to be added 'by hand' to each one made. The one mod I would not consider adding is the Murata regs. They are not cheap, and by the time you add in production cost etc., the price at the point of sale would have shot up to a different price band. I would leave those bits as a mod.

It takes a couple of months to go from design to finished goods. So if we can come to a quick consensus, maybe we can have a production based prototype ready for testing in the summer, and the final version in the autumn/winter.