Look here: Courui + 86mm KD reflector + camera parts; Say Cheese!!
Here is the courui D01 moded from 340 to 625kcd with 86mm bezel and a deep reflector. From the default one. 13cm bezel should power through 1mcd with ease. The main problem for me is the surface brightness of the led. Here the xpg2 is used with fet. It can even be improved with buck driving up to 5.5A and provide more throw. Dedomed also. Then we go to the Xplhi, which is larger and smaller (?) brightness. Then we go to the XHP35hi which is even larger and even dimmer!
I am sure that most modifications (and the first ones) will be with swapping the emitter for an XPG2 and improving throw compared to XHP35hi about two-fold.
If the tn42 provides 700cd, with XHP35hi, then with larger, and more importantly deeper reflector, and a bit more current in the led, it should easily achieve 1mcd. With XPL even more, and with 5.5A XPG2 dedomed, a whole lot more than 1mcd. The mod above in the thread will tell you the improvements of a deeper reflector.