Ultrafire copied the design from another manufacturer and may have designated their own model number as “C8”, but the Ultrafire C8 is just a cheap clone of another light that far preceded it by at least a decade.
Can you recall which light that was?
Phil
IIRC, it was US made and possessed a price and quality far higher than the dozens of Chinese clones being hammered out today. There are probably over 100 clones of just the Ultrafire C8 alone. 
My particular interest at the time was to consider modding it as a secondary remote battery pack diving light to add redundancy to my primary. It lacked dual seals at each connection so I passed. Ive searched a few times and still havent found any references.
No hurry on finding the light, just post here when you remember.
The success of the C8 design shows in the number of clones it has brought; perhaps it is the most successful (or at least the most prolific) LED Flashlight design which is what makes this thread so interesting 
Phil
dotn you think,that the most succesfull led flashlite design is sipik sk68???)
I mistook this for another.
"Most successful flashlight design." Hmm...
My pick depends on your criteria.
If you go by number of units sold, the SK68 may be the one. If you measure by gross sales revenue, that may still be right. The C8 probably gets closer when you measure net profits. But these are all guess. I have no facts upon which to base them.
Yet another measure would include quality. A good C8, such as the models from Convoy, XinTD, and ThorFire, is a good flashlight at any price. The SK68, however, is only a good flashlight when you factor in the budget price. By this criteria, the "design" of the C8 is "more successful" than the design of the SK68.
It's a darn good design.
The C8 is a scaled down version of the Ultrafire WF-500, which was originally an incandescent light that took two 18650 cells. It has a larger head than the C8, with about a 50mm diameter reflector. LED versions of the WF-500 appeared because you could replace the original reflector and bulb with either a one LED (Cree XR-E, remember those?) or three LED drop in module. Other models appeared such as the WF-600 which was a LED version of the WF-600, either with a much deeper reflector and a WF-600 or with a 3 LED drop in module. Then the Ultrafire C8 and C12 appeared, followed closely by many clones with different *fire names but seemingly identical build, the race to the bottom came later!
When the first *fire clones first appeared nobody knew whether the had the same manufacturer or not, but the clones were quite a bit cheaper even back then.
there was also an Ultrafire C2 in the same form factor iirc (I'm sure I still have one somewhere).
I wonder how many AA and D cell maglites sold? The numbers must be astronomical.
Isn’t the SK68 a clone of a Nitecore?
As far as I can remember, Ultrafire was the first to produce a C8. That very ugly and medieval style was a trademark of the original Ultrafire brand name, before they became history, to be copied by everyone and Ultrafire became just a brand name that everyone stole and used as their own. This was back in the incan days of CPF. I think the led was the Cree XR-E at that time, but I could easily be wrong.
Let's try to stick to the C8 here, and leave the "most successful flashlight" for another thread.
Thanks.
@FlashPilot: Have you had any luck in remembering the precursor that you recall came from the 1990s?
I don’t have an answer to where the design originated from, but at that time a lot of designs appeared to be of incandescent origin and adapted to host a LED and driver.
It’s weird to see one particular design copied by different manufacturers for so long but there must be a reason behind it like good sales figures and/or the schematics became ”open source”.
I also wonder how many designs are offshoots of the C8 such as Sofirn C8F and Convoy C8+.
This is a comparison of Cree XR-E throwers from 2007. The two Dealextreme light look just like a C8. I think they were made in response to the other, higher quality throwers from back then like the Tiablo.