First off, this was really easy to build! I'm the kind of guy that has trouble hammering in a nail straight or putting together something from Ikea. And I don't have anything more than basic tools.
Here's what I used:
Element - 1/4" aluminum rods from Metal Supermarket (I wanted 3/16" but they were out of stock), about $10
Backbone - about 5 feet of 2x4 in 3 pieces, left over from a previous project. Joined in a "T" held together with 4 long woodscrews
Reflector - a piece of board from Rona, 2' by 4' (about $4) - the kind of stuff that's used for backing on a bookcase, plus ordinary tin foil. Tin foil attached to the board by duct tape, the reflector attached to the backbone by 4 nails
The rest - 6 1.5" #7 woodscrews from Home Depot ($2), 6 large washers from Home Depot ($1), one balun from my stash of 1970s tv parts
Hack saw to cut the rods to length, and trim the board to 2' by 3'
Electric Drill to drive in the woodscrews to join the 2x4 pieces
Hammer from the nails to attach the reflector
Scissors to cut the duct tape
Screwdriver to attach the element and balun
I bent the rods by hand by measuring and marking the points with masking tape and found a suitable hard spot outside my house to use as a pivot to make the sharp turns (not so easy with 1/4'
I did some preliminary tests against my incumbent CM4221 and my SBGH is a worthy challenger. I'll post the results as testing progresses.