Hart Leathercraft might have something for it.
Dean The Vaping Biker Todd showed a mod holster they made for him and I was impressed enough to bookmark them for future reference.
EDIT - Here's the post about Todd's holsters
"Two cases commissioned by a vape reviewer (Mark Todd - 'Todds Reviews' on Youtube) for his 'Billet Box Vapor' vape mod. The brief was to make a case containing his 'Phoenix' logo and it had to be a 'sleeve' not a box case, so it has some internal stops to prevent the mod slipping through the case if the cases stretches over time and relinquishes its friction fit. All hand carved and dyed, with one of the cases getting an 'antique aged' effect which is designed to wear with time to show the grain and texture of the leather."