I have been buying some drivers from Lexel, with Bistro OTSM HD, to mod tailclicky flashlights.
Those are not necessarily “budget” as the biscotti drivers but they are very good!
Besides that, they have the possibility to configure the modes you want to use, according to this: [UPDATE:v1.7.1,Q8&1chanOTSM]bistro-HD, bistro your way. OTSM, eswitch(devel), Vcc reads, safe_presses, turbo timeout...
I am currently using it on my Tool AA V2.0 (a 15mm one) but he has them in bigger diameter.
You can also look to the MTN Electronics drivers, but some of them are more expensive and some are also out of stock!