I built a sissy yesterday outta scrap, I didn't know the small sissy is SOLID aluminum! So I just put 2 bolts on it, its only temp anyway untill I get my new project started.
Its about 10" tall off the seat, the 3/4" square steel tube is from lowe's, cost about $10 for a piece 3' long. I used scrap sheet steel and made "L" brackets that I riveted in.
I used a dremel tool to cut it, and a $20 manual rivet tool, lowe's also sells the sheet steel in small sizes for fairly cheap.
Tools I used: Dremel (all the cutting), 12' tape measure, battery powered drill, sand paper, rivet tool, roofers square (didn't really need it tho), some hand clamps and a vice grip plier to hold it still on occasion, and a file to keep the edges of sheet smooth after install.
Oh and some black paint, spray can stuff.