Hi's, I understand with the cost thing, a worldly trend, everything is getting expensive.
Just ma 2 cents
Ben does what he wants.
Ben builds quality under OMD, it is the best you can buy and I'd be f'd if I could make it, he has a quality workshop and great thought and skill set.
With alloy, well stainless is an alloy lol but a soft alloy like ya request will suffer wear in the lid bearing recess over time with bearing removal, the case hardened bearing will wear the soft center post with on/off lid and the grinder will be scratched and looking like shit in a month and OMD has lost face and reputation.
Do without an unhealthy luxury once a week and drop the coin in ya ol mate fundage jar.
[ or I'll have to buy all the aluminum omd grinders n bin um lol
Bens thoughts will be far more interesting than mine.
Good luck ~ All the best