This sort of thing ?
Line Lasers is what i think you are after
Not particularly powerful, dont need to be - just designed for the purpose
Full industrial sort here - at industrial prices
I am sure that eBay would have "line lasers"
Just looked - heaps to choose from starting at pcoket change
http://www.ebay.com/itm/100MW-650NM-...item27c34d1455
http://lap-laser.com/indallen/indust...d/default.html
http://www.carterproducts.com/produc....asp?cat_id=77
http://www.carterproducts.com/product_list.asp?cat_id=8
Check out the the full 2D projectionunit !
http://www.carterproducts.com/produc...id=16&cat_id=7
Also there is a 3d unit
Draw it up in CAD on the PC and project it out onto your timber/steel/plastic, and start cutting !
Or go to Bunnings and buy a cheap Chinese circular saw that has a line leaser built in and rip it out, keep the saw for yourself !
Cheers