I would like to recommend that you try McGizmo's McR-10R reflector found at the Sandwich Shoppe. It is a 10mm reflector specifically designed to work with the Rebel emitters. It fits very nicely into the head of the Solitaire after you remove the stock reflector. You may have to very lightly file the outside diameter of this reflector in order to fit some Solitaires with different colored anodizing (for example I had to do so on the black color but not the blue). This may be just because of machining tolerances also, since the black colored anodized layers on Mags are usually the thinnest (colored and lighter colors have thicker layers).
Slight possibility of filing aside, it is totally worth it. It is somewhat focusable, but once you find the best focus, the beam is beautiful! It has a somewhat broad, but even beam, with a nice corona surrounding it. The beam is very useful, and it still is small and intense enough to allow you to see into the woods or a dark alleyway. The beam from this reflector is very smooth, and I do not see any ugly artifacts in the beam (very clean) considering the Rebel's TFFC die can produce some ugly artifacts (due to those dark spots on the die -vias).
These reflectors work great for both the Rebel emitters as well as the new Cree XP-E emitters. Can I also suggest that you try the new XP-E? They are a bit more fragile due to the use of bond wires, but they use more efficient dies. The Q4s I got are very white and produce an even more tighter of a beam than with the Rebel. Cutter (if you want to deal with them) now sell R2 binned XP-Es now. If the emitter is perfectly centered, then you do not have to worry about shearing off the dome. For the Rebel, this will not totally kill it. In 3 samples of Rebel 0100s, I lost the domes. The phosphor stuck to the die and they continued to function (albiet dimmer due to the whole index of refraction with the dome thing). With the XP-E, if you shear the dome, or maybe just press on it too much, the bond wires can be broken. With the bond wires broken, it will be rendered useless. With the emitter centered, you will be good. The emitter seems to be pretty durable when working with it by hand (while I was experimenting with it).
I modded a solitaire to use a Rebel 0100 emitter soldered to the thin MCPCB found at the Sandwich Shoppe. This MCPCB was then epoxied to a long section of anodized metal cylinder (found at McMaster). I had to increase the diameter of the hole found in the Solitaire so the heatsink would fit. I planned on running the Rebel DD from a 10340 li-ion cell for simplicity. Later, I hoped to build another using the same cell but a small 350mA buck driver, or a AAA cell with a boost driver. For this prototype, I created a positive battery contact at the base of the heatsink and fed a wire up through a hole in the heatsink. The flashlight body was the ground. Since the solitaire lost its twisty on/off function long ago, I had to implement some sort of switch, so I used the small 11mm clicky found at DX and implemented it into the tailcap. I milled a hole into the tailcap and shortened it (I removed the long smooth portion after the threads where the ground contact was made). The clicky works well, but the tailswitch is not as nice looking as before.
With my prototype, I drive the Rebel pretty hard with a full charge on the li-ion cell. I estimated that the Rebel had seen enough current in the first couple minutes of operation to produce 200+ emitter lumens. The reflector is relatively efficient, so the output is pretty bright (and extremely so considering the size of the flashlight). Due to the DD, I do not see runtimes past 20 minutes, and I am abusing the cell a bit when fully charged. This is not a practical light, but it works well and it is a mean little beast. My Q4 bin XP-E is located in a Mag 2AAA with the same reflector. I added the XP-E to the Terra-Lux AAA cell drop-in. The boost converter sends a decent amount of current to the XP-E to provide useful amounts of light while allowing for good runtime (not measured).
Good luck with your Solitaires. I think that you could have a stellar product if you used the XP-E or Rebel with the McR-10R reflector without increasing cost any. The beam you have with your prototype looks somewhat ringy if that matters. Outside, it is difficult to tell because the picture is overexposed. BTW, I really like how you created the pill. The heatsink looks very nice, and it is great how you kept the twisty on/off function intact. Do you use thermal paste on the heatsink, or would that make it too gunky for smooth operation? Thanks.
Cheers,
Tony
EDIT: One more question. Is the dome still intact on your prototype pill? I looked at the picture for a while after posting and I am having trouble distinguishing a dome. I hope it is there, and you intend on having it there in the production models. When you lose the dome, you will see a decrease in light of up to 30% and the tint will shift to a warmer white. It will produce a smaller beam, but it is not worth the decrease in lumens. It is difficult to see the Rebel with that epoxy or spacer ring you have on the top of the emitter. Oh, and the previous poster made some good points. Currently, I am out of the market as well. But by the time you get several production units sold, it may change for me. I like your pill design! Thanks again.