XHP70-50 is a 6v emitter, you would need a really good boost driver to run off 1 cell!
You could run a SST-40 at 8-9 amps with a FETDD driver and a High current 26650 and get 2500lumens and decent throw!
Dale (DB Customs) has a Q8 doing over 11,000 lumens with 4 SST-40s in his Q8!
Q8 modding See Post 1288-1289