cheap 5/8 inch square stock at Home Depot

The Aeroquad arms are made from nice, thing 5/8 inch chromed aluminum, and happen to be the cheapie (err, "Best Value") towel bars from the local Big Box hardware store.

I found them in Home Depot.  They're unsurprisingly in the Bathroom Fixtures section.  They come in 18, 24, and 30 inch lengths.  At the Emeryville Home Depot they were $2.50, $3.50, and $4.50 respectively.

They're hidden away in a box on the bottom of the shelf.  Here's what the display looks like. 

Here's the stock number for the 30 inch bar.