There are at least two 22mm designs freely available on BLF for you to assemble yourself:
- WarHawk-AVG expanded Mattaus’s BLF20DD to 22mm here: WarHawk-AVG - BLF 22DD discussion thread
- I produced a 16*7135 driver in 22mm specifically intended for this light over. Sorry that the thread is badly organized, but it’s only 3 pages: 22mm 16x 7135 driver for F13 flashlights - [released]
Your other option is to use a smaller 17mm or 20mm driver. You can either use a contact PCB (like these 21mm ones from IOS?) as bibihang suggested or you can just strip the stock driver and use that in lieu of a contact board. IIRC there is enough space for any 17mm driver you want.