No BX gear drive. There's no way to put a clutch on the front of the engine. The engine sits in the frame backwards, flywheel toward the front of the tractor and fan/radiator in the back of the engine area.
Besides, for what a BX is designed for, the HST is perfect. I wish my massey was HST as I use it mostly for loader work, and changing directions often with the gear drive and stiff clutch sucks.
RARELY see an HST with a failed/burned clutch. Often see gear drive tractors with failed clutches. Most of them are DT's, some are GST but those are a rarity. Most that own a DT tractor with a loader don't properly use the clutch...many slip the clutch while driving into a pile of dirt/rock/gravel/etc with the bucket. The slippage is what kills them, over time. HST you don't need a clutch and actually some of the newer tractors with HST transmission do not even have a clutch pedal anymore.