Hi AdierR, Im using a 2 stroke engine simulation program called MOTA, it has a utility for designing pipe segments.
there is a free demo you can download, from http://www.iwt.com.au/MOTA.HTM the pipe designing part is not crippled or restricted.
Can be usefull for other general stuff.
A sheetmetal place would charge too much as there is a ton of welding, lasercutting seems to be theway to go as it doesnt get distracted