Well, I knew these products for a while now, but only after taking a look at this pic I realized that a product that contains a X5 reflector in a 18650 body actually exists, and it's called MH20 / MH20GT ! 
Exactly what I was looking for:
source of the pic: http://www.taschenlampen-forum.de/threads/klarus-xt11s-pa-review-thread.48368/page-2
Not an overdriven LED like BLF X5, but still a XP-L on the same size reflector and a decent output. I've been wanting something of this size since the beginning, but the smaller battery type prevented me from buying the X5. Now I have just added also a MH20GT to my new flashlight collection.
I was also considering a Manker U11 or Nitenumen NE01 for this, but the MH20GT has a much nicer throw according to pictures in every review by far (only the GT version, normal MH20 version looks the same as Manker and Nitenumen). This 2-way button is way more practical also then the tactile and slow interface of Astrolux MH10 / Imalent DN11 new products.
Also thinking about portability, moments before I have bought an Astrolux S1 (BLF A6). Nice drive, 1200-1400 lumen in a very compact body. More floody, and it will be very handy. I though about a triple XP-L Convoy S2+, but it would be too much heat in a small body that would limit a lot its use.
By the way, just a wrap up: up to now I learned so much about flashlights thanks to you guys that even before my first one arrives I have already ordered a lot more. I guess I became addicted, but I'll stop here because that's enough 
. List of all the flashligths purchased up to now:
- Astrolux S2 (BLF X6), XP-L HI 3B
- Eagle Eye X6 triple XP-L V5 3C on XP32, copper spacer, Ledil medium optics. (modded and assembled by forum member kiriba-ru). Maybe I'll try to change the optics to Ledil cute-3 ss (already bought), and maybe even polish it.
- Astrolux S1 (BLF A6), XP-L 3D
- MH20GT, XP-L cool white option only
And for photography-related use (including home-studio and macro shots):
- Jaxman E2, Nichia 219B 5700K
- Astrolux S41, 4x Nichia 219B + 18650 tube
- some BLF 348, Nichia 219BT
- some flexible holders like this one (I hope they can hold a flashlight)
Chargers and batteries:
- Xtar VP2
- Nitecore D4
- 2x Samsung INR18630 30Q Unprotected, button top
- 2x Sanyo/Panasonic NCR18650GA Protected 3500mAh (8A high discharge)
- 2x NCR18650B Protected 3400mAh
- 1x Nitecore NL189 18650 3400mAh
Let's see how they will compare between each other now. Once arrived everything I'll try to make a post comparing them all!
Thanks to everyone who helped me so far!