Seems like the AA version is everywhere but the 18650 is hard to find. I checked T-mart but they don’t have it. Manafont doesn’t sell it anymore either. No luck on EBay.
Why not just buy that one? Sorry I can't be of any more help. :)
have you found Google? 
auni2010.ecrater.com - XM-L version (maybe - sometimes don't get what's advertised)
DX - XP-G version
wholesale-ledflashlight.com So I found this site. $7.67 + Shipping Cost (I wonder what S&H will be?)
Extra: BLF review (here)
I wanted to buy from a trusted seller. I would rather avoid Aliexpress. Hoping to find a place like Manafont or even a USA seller. Figuired this would be everywhere but seems like it is being discontinued but not replaced with anything similar.
Trying to find a 1 x 18650 headlamp is way harder than it should be. I shop for headlamps and there are hundreds of the same crap in 18650. They all look the same and most are mulitple 18650 with a zoom and battery pack on back. Don’t want that at all.
You mean you like the headlight but worried 18650 batteries are hard to get or find? then I have a suggestion ,if you really like the headlight ,you can just buy this and buy a pair 18650 battery and charger.There are many 18650 battery sellers