Alternative to drilling frame for dropper?

My next bike will have one of those stupid headsets where all the cables run through the headset.
This made me think that maybe if you bought the top half of the headset you could then run your dropper cable through that.
Would there be issues at the BB?

Would there be issues at the BB?

Depends on the frame. Some/many carbon ones have a sealed BB tube, so you wouldn’t be able to route through that area.

Surely if it’s modern enough to have one of those headsets it’s modern enough to cater for internally routed droppers?

I think the OP’s mooting using the routed headset from a different bike, on one that doesn’t have a pre-drilled hole for a dropper.

Can you drill out a seat tube bottle boss?

I don’t need to do it just thought it might help someone else.