Material for 3d printer structure.

Hi, I am very unsatisfied with current commercial/consumer 3d printers and decided to design one. I was curious as to what the cobblebot 3d printer, and the taz 4 3d printer bodies are made out of (what are those metal bars called and is there a place online to get them cheap in usa?). Secondly, would you say linear v rail makerslide systems with the wheel system is smoother movement, better quality print, and more cost affective than smooth rods? And is the material that taz 4 and cobblebot are made out of all makerslide? or a combo of both? or neither? Also any other design advice from experienced or knowledgable reprappers/engineers on creating a sturdy structure, cost effective, and, good quality? lastly would you say I should just I will release my designs as open source, share a like once I have them finished, as a reprap printer! Thank you so much for your time!!

UPDATE: is there a custom heated bed manufacturer? I need a 20x20x20 heated bed? Also what is the best software to design this printer in? I have paper drawings but want to make it 3d drawing in a cad program? Any recommendations for easy to use, effective cad programs besides sketchup and autodesk?

Edited 2 time(s). Last edit at 07/12/2014 01:04AM by caleb12134.

those metal bars are called "aluminium profile" in switzerland we called the "item profile" cause "item" is a famous brand of that aluminium profile here. It's used a lot in automation industry.
I don't know any usa reseller, but i am sure you will find them easy in the us.
Also I am building another 3d printer wich use alu profile, it's looking great for now

The extrusions are called T-slot, and are available in the USA from Misumi, 8020, Bosch/Rexroth, and a few other manufacturers. Misumi will sell it to you pre-cut to your exact specifications for a fair price, and was even giving away a free $150 worth of materials to RepRappers in a promotion that ended a few months ago.

You should look at V-slot instead, since it has custom wheels that ride inside the slots and was designed for combined linear motion and frame applications.....