I've just bought a 40ft pole from a fishing tackle dealer in Scotland, (it wasn't for me, so I haven't got the invoice and I can't remember who they are
, but I think Jeff Brimble has dealt with them?). It came with a simple aluminium gooseneck, just a length of tube bent to the right angle and with a screw cone cemented in the end, and then the other end slips over the top of the upper pole section.
So:
What's wrong with drilling a hole in the gooseneck and passing the pole hose down through the pole? You just need to feed the hose through each section as you add it to the pole. There you have it: internal pole hose just like a telescopic one.
Or is there something I've missed?
Cheers,
Ian