Thanks for the replies and the links!
I'm particularly an enthusiast of "fast prototyping" in the sense that I want to do quick iterations, so despite having been trained pretty well to do hand-milling/lathing, I am looking for faster approaches. the links you sent are a good basis for understanding materials for lasercutting and such.
I was interested in seeing if theres an option to doing this in-house, which makes waterjet cutting less viable (but when you need it, I guess its there). Plasma cutting is another tool, and heres a link to a promising one: gotorch.com/?gclid=CM3S2tHFm ... fgod158Adg
setup cost is about $5K, and countless hours to learn, but it may be a permanent solution.
Regarding the prev. comments about steel, one way to get around the weight of the metal is to sandwich plywood in between thin sheets of stainless steel and fasten it together -- it does a good job of being quite rigid and getting a bit of both worlds (metal strength, wood weight -- you can hole-out your wood to make it lightweight). its a bit more work, but will get the job done. Also, you can then use a laser-cutter only (given that you have a powerful enough one).
If theres any other tips to achieving aluminum-like performance, i'd appreciate any other tips. Thanks!