Super simple, and cheap adapter to make a 4 meter long "selfie stick".

Use a 6 meter fishing rod (telescopic) and remove the two thinnest sections. (I used this: http://www.biltema.se/sv/Fritid/Fiske/Spo-och-rulle/Metspo-45951/)

Use the printed part and a 1/4 bolt of suitable length ( I cut mine with a dremmel).

Use tape or Hot Glue (or epoxy) to fix the part to the fourth section. The inner diameter of the end of this section is roughly 14 mm.

This will give you a versitile boom to mount anything (not heavy) with a 1/4 inch thread.

I'm using it for a GoPro for shots from up high, and with a microphone as a boom microphone.

If you want more stability I guess you can use only three sections, but then you need to modify the diameter (or use some tape).

I'm using a fiberglass rod for very little money, but you could also use carbon fiber to increse stiffness, and you may need to change the diameter then as well.