There's a great source for fibreglass poles in Canada at Princess Auto Stores. They're in the Surplus section, and come in 4 foot lengths. I'm assuming these would be available in the US as well.

I've built a top piece for them, so they can be guyed, and it also includes some holes to mount antennas. I've sized the holes so they can be used with the 3/8x24 CB radio connectors, which also fit hamsticks. This way you can get a vertical dipole up in the air.

I designed it in FreeCAD:

And 3d printed the prototype:

Then I sent it away to be laser cut out of aluminum.

An assembled pic:

Note that the insulator goes on the top side of the topper, this insulates the radiating element from the topper, and the bottom hamstick attaches to another hole in the topper.

And in the field with some hamsticks: