Mr Drastic Sports
I beleive this may help:
http://www.jeffalbro.net/cnc/rfqs/
I was just looking at it. I too will want some parts soon and am hoping people here can help me. sorry for the 'dig', but its always weird when people asking for help are anything but gracious...
Anyways. as noted, parts get alot cheaper in quantity. That said, I think you should be able to get parts like those bumpers for around $5 each in quantiy of 5. People here with a decent aluminum-cutting cnc router could cut sheets of blanks of those. say 10 per sheet, and then form them to that simple profile using a simple tooling and press of some kind. if i had the cnc machine, i would happily either adapt my largish hand-press to do this, or purchase an inexpensive press that could do it.. for a die of a profile that simple, i would consider actually sawing steel angle and bolting it togehter... powder coat with my harbor freight powder-coater rig.. i would demand a minimum quantity n these things.. so i could hire a friend to do the grunt work..
Checking Mcmaster.com, the material is quite expensive to begin with:
Thickness .09"
Thickness Tolerance ±.0040"
Length Tolerance ±1/16"
Width Tolerance ±1/16"
Material Corrosion-Resistant Aircraft-Grade Aluminum (Alloy 7075)
12" 12" Square Sheet 8885K14 $29.95
24" 12" Rectangular Sheet 8885K21 47.83
24" 24" Square Sheet 8885K27 86.05
48" 24" Rectangular Sheet 8885K34 158.84
48" 48" Square Sheet 8885K41 283.60
8' 48" Rectangular Sheet 8885K47 512.28
You should do some leg work and look for more sources of material. Many shops probably go right to something like mcmaster to base their quote on. Also, you can consider making things in alternative mateirals. Say carbon fiber. Then the part gets laid up on a mold made of special modeling board, vacuum bagged, and the shape cut with a cnc.. this can be cheap and interestin.. i mention that because i noticed it on your ebay auctions.
if i had the 2 machines i am currently building as fast as i can done, i would talk to you about doing these. if the material was cheaper, i could see machining these things 10-50 at a time out of a sheet, and bending them into a smple jig on a hydraulic press... even a small hand press may work...
stupid waiting around for good stuff to show up on ebay!