I've designed and 3D printed a ring light/flash in OpenSCAD made for 1 Watt star LEDs, it's simply a light with a switch, but I might add some electronics to make it a real flash some day, but for now it's not a big deal.
It's customizable so you can change the number of LEDs and/or the diameter of your lens, there's also a module called
flex_holder() which is an adapter for the ring flash (printed in Ninjaflex) so it fits snugly on the lens.
I've simply taped the batteries (4 AAA) to the battery compartment part, which I might change to something better... The light given from it is a bit too yellow, but it's quickly fixed in Photoshop.