Shakespear makes a thing called a Wonderpole for crappy fishing.
They are about the right length for a cane when closed and can be from 10 feet up to 20 feet long when extended.
http://www.shakespeare-fishing.com/products/rods/wonderpole.shtmlThey are on the list as TSP for telescopic pole.
They are a straight fishing pole with out even a real seat or guides except the tip, so not for long distance casting.
(although there are some tricks that let you fly fish and surf cast with them)
I have no idea if it would work for you because they are not really made for heavy fish but it might be worth a look.
If your fishing line is less than the strength of the rod you wont worry about the rod, and these poles have a lot of springiness in them.
Most fishing tackle places should have them.
There is another range of wonder poles made by The American Flag & Banner Company that is a lot heavier.
They are intended to fly flags from or be used as radio antennas.
I suspect they would be too heavy for what you want, and they are still long enough to use as a walking stick when closed.
http://www.wonderpole.com/index.html