aluminum tube

[kaptain Jack]

Try luggage stores, some small cases have telescopic retracting handles, most are square (I used one on my wrecker build) but you might be able to score a round one as well.

[arf1201]

You might try a fishing rod holder, I have found different sizes and weights of telescopic rods.

[JAMMER]

http://hobbymetalkits.com/ here is a place were I found some telescoping material best to call and tell him what your looking for I met him at the York PA meet. Ed