I drew it up in Fusion360 and a friend 3D printed the holder a while ago.
It combines a xenon flash tube (Yongnuo YN-467) and 10w Led (Cree XML-2). It fits perfectly in the 100w halogen light house of my Olympus Vanox AH. The flash tube is located exactly where the original 100w halogen bulb would sit. This allows me to quickly switch between led/flash and 100w halogen simply by switching the holders. The led die and flash tube can easily be moved back and forth, and rotated to move up and down, and the collector lens on the Halogen lamp housing is focusable.
As you can see, the holder also has a slot for a 25mm diameter 420nm long pass filter, which should get rid of any unwanted UV light from the bare xenon tube. Visually the 6000k led looks pretty good on its own.
I made an earlier version 1.0 where I used the collector lens from the incandescent light house, but this was not a good match with the flash tube size, as it did not fill the back focal plane. Now, with the halogen lens, the flash tube is more magnified and looks much better at the BFP:
It looks very good visually, but I haven't tried it for photo yet.. Hope to be able to use the flash at 1/16 or less, to get nice short exposure times. Will update with the results at some point!