looks great! if i understand the orthodox use of the term, i have not seen a catadioptric design for a flashlight before this one, as opposed to TIR-style independent path optics. other combinations of reflective and refractive optics have been tested (for example EBRZM-16 just over 1000 Kcd thrower, which might fit some definitions of catadioptric). i did just find these optics for sale however, and i’m not sure how they define the term:
http://www.roithner-laser.com/led_highoptic.html
is the collimator in your light there just to correct aberrations? does it introduce any (chromatic)? it looks lighter-weight than a TIR.
looking forward to seeing the beam pattern from this!