A thought from the scrounger gallery. If you're going to do heat shields as Dan mentions, you can use stainless instead of aluminum. Really thin stainless doesn't weigh much (if any) more than aluminum that's thick enough to be stable. Added advantage is less re-transmission of heat.
Now for the scrounger reference. Check the local Wally World or other discount chain for a cheap stainless 'stock pot'. It cuts & deburs easily with an abrasive cutoff wheel, and you can shape the pieces with your seaming pliers, vice, etc.