Dropper post cyclocross
 

Hoping to not create another difficult project, spanning months, requiring custom fittings and costing several hundred cheddars: have a aluminum cyclocross frame with one of those idiotic pulley wheel fittings at the lower back of the seat tube. I have long since converted to a top pull front deraileur and so the threaded pulley braze on is plugged with an m5 bolt. Can a dropper post use that hole for the cable? Thank you.

You might be able to hack it, but it'd be a challenge and may not work. Maybe get Yokozuna Premium Cables, Housing and Brake Pads and see if you can run it through the hole? Even then, the sharp bend would be a problem, though it might work. As ugly as they are, I'd just do an external dropper.