Are you intending to make a "focusable" or variable beam angle capability unit like the Sola model?
I can suggest leds and driver to make a unit that is brighter than the sola and perhaps better suited for video color rendition in the 3000K range with High CRI index. I have built one myself that delivers 3200 lux at 3 feet, 90 CRI , draws 26 watts and can operate from 7.2 volt camcorder battery. That Sola needs 12 volt DC source or more to make it function, so a rear mounted battery on the light is out of the question. That unit I have seen on pro ENG cameras and fed off the brick 14.4 battery or belt packs. Depending on the video work you intend to do, I would choose my leds wisely. Are they going to be 5000K+ for outdoor or 3000Kis for tungsten balance ? I have also made a on-camera light that has a 3 position switch for 3000K-4000K and 5000K using 4 leds with
medium beam Ledil Boom reflectors. 2 leds are 3000K hi CRI and 2 leds are 5000K. A 2p2t on-on-on switch takes care of either or both on function.
You may want to consider Taskled H6CC driver and add a 50K log pot for dimming. How about checking out either the Cree MT-G's or the XM-L's.
With a single Sony NP-F970 camcorder battery on my unit I get well over 2 hour run time at full pop. If I dim it down a bit, I gain big time on run time.
If you really want to make the light focusable, then perhaps a single large die led may be needed along with a mechanical fresnel positioning device. You can also achieve a 2 mode wide or narrow beam like I did on another light by using 2 different reflectors like a wide Ledil Boom and a narrow Ledil Boom and also using that switch (on-on-on) for beam choice.
On the MT-G-s, I had to ream out the Ledil booms using a stepless drill bit for the leds to fit. I was worried that the booms were not designed for the Mt-G's but they work great and the narrow beam throws out to well over 60 feet. Make sure the housing is well heat sinked, them leds heat up very quickly.