Josey,
The FBOP was indeed a modification to the OC design, just as you say. And there is about a 1/4" to 3/8" of lost space due to the need for a threaded tail-cap (permanently attached) behind the switch-core and bottom plate.
However, TigerLight would take the stand that the rear-position switch is more "tactically correct", whether or not the pepper spray is attached or not.
But, more imortantly, TigerLight is all about the pepper spray version of the light. The FBOP was (and will remain) an after-thought of sorts. By this, I mean they are happy to offer it, but only if it can be streamlined with the TL-OC production.
That won't change, no matter how I advise them or what I design. However, there are some designs under consideration that will address some of these concerns. I'm afraid I can't say any more than that at this point.
Oh well, in any case, one must choose his or her battles. I initially wanted to ensure that TigerLight had a top-quality battery pack, and a properly focused, long-throw lamp module. And next, a higher powered LA to take advantage of the top-quality battery pack. And these are exactly what I accomplished. And I'm pretty happy and proud of that.
Next, our attention turned to developing an integrated fast-charger, with all the electronics inside the cradle, with no extra box needed, and that would work directly from the cigarette lighter in the car.
THAT has now been accomplished, and we hope to be able to have this on the website sooner rather than later. I will post a thread about the new fast charger at some point, but the short of it is this: zero-delta V peak detection scheme specifically for NiMH cells, 2 hour 15 minute maximum charge time (most often sub 2 hours), and will also work from 24 volt hummer adaptor. Switch mode circuit generates almost no heat. Red going to green LED indicator. Same exact plastic harness. Nice side position universal switching supply wallwart (works world-wide, takes only one space on outlet strip, very light).
So once that is out and production of that is smooth and underway, we can consider the Gen 2 of the TL gold system. Lots of very cool ideas floating around for it. Very exciting. But going from concept to reality for a production flashlight is infinitely more complicated than I ever would have at first imagined.
Still, even as is, the TL FBOP is a really great light--the best value per dollar in a big gun incan IMO.