You are definitely too picky! I'm not sure why it needs to be aluminum or can't have much plastic. If it doesn't have plastic it is likely brushed aluminum which your fingerprints will etch into the case. Nothing worse than that imo.
Since you are confident in modding pick whichever case you like the aesthetics most and roll with it. Fine tune and customize to your needs!
I guess my tastes may be rather cheap in your eyes but I switch my case quite often. IN the past 2 years I have went Corsair Obsidian 650d > Fractal Design Define Mini > Bitfenix Shinobi Window > NZXT Switch 810 > Corsair Carbide 200r. All of them I have been more than happy with I am just upgrade happy and a nut for aesthetics. Honestly I'm lovin the 200r. It was so inexpensive, it's light and small and has some decent features for the price. Also very modder friendly.