what style do you like?
For instance VWR lab equipment is pretty chic.
High end option : die cast, other type of casting, welded metal (i.e. you work with a sheet metal guy to make contours or setup a line with presses).
Low end or light option : plastic shit. Extrusion is $$ though you need volume to absorb costs.
The enclosures look like shit because their usually cheap extrusion. You can make very nice metalic objects using tools like sanders, benders, welding, polish, etc.
A hybrid of plastic and metal thats 'high end consumer' is proxxon tools.
You can make very nice thin enclosures out of aluminum, titanium, steel, etc with tig welding. Those welders have settings to do like 0.005 inches thick metal. For small production I guess it would be welding together laser cut nice looking sheet metal?
It will depend 100% on volume. An auto body shop can pretty much make a Iphone case IMO. Costs will keep going down the bigger your volume is because specialized machines will reduce fine finishing requirements (polishing welded curves) and reduce the number of welds or joints you need.