The British RED specialist KipperTie announced an active EF or PL lens adapter for RED cameras, that comes with an integrated ND filter wheel. The KipperTie REVOLVA is suitable for any RED Scarlet W/Epic W/Weapon DSMC2 model.
If you are wondering how to place several ND filters (and optionally also clear glass) in an adapter, you should take a closer look at the product pictures. The mountable filter wheel stands as a larger disc next to the actual beam path of the mount:
This means that the filters do not disappear as easily as with many competitors in the housing. But still more practical than changing filters in a matte box. Nice additional effect: When using filters behind the lens mount, stray light and reflections are virtually eliminated.
However, this flexibility has its price. Pre-orders for 2.000 UK Pounds are now accepted. Delivery is then scheduled for the first quarter of 2018.