I drove 20 minutes up the road to by a bushel (US, not British) of U.S. No. 1. apples, to make apple cider. On my return trip, I stopped at the hardware store to buy a 2 lb box of 1-3/4" ring shank 12 penny nails. I used my 7/8 hole kitchen planer blade to grate the apples, then squeezed them for an hour and a 15 minutes at 30 psi to extract the juice. For good measure I added 2 tablespoons of vanilla and a pinch of salt. Then I drove the nails into grade C 2x4 joists (whose sizes are 1.5 x 3.5 inches, with a 1/16th inch permissible tolerance in sizing).
I'm going to start by ignoring any quantities above that are not involved in any sort of calculation. Those are outside the scope of the problem and proposal. And I don't care what anyone thinks of that. The only calculation I see here is 1.5 in x 3.5 in = 0.00339 mm2. The fact that joists are called 2x4 even though their nominal dimension is 1.5 in x 3.5 in is also outside the scope of the problem and proposal. Come on man, you think you're the only one who knows examples like this? How about 1/3" image sensors? How about display diagonals? I know about these things, and I know that they do not need to be accounted for in a standard, language-supported representation of units. Units have infinite precision, so grades and tolerances are also irrelevant. The units you mentioned are: minutes bushel (imperial) bushel (US) psi tablespoon pinch (it's a stretch, but okay) foot inch 7/8 hole - this is a specification, not a unit 2x4 joist - specification, not a unit grade C - specification, not a unit 12 penny - Wikipedia calls it a unit, but calculations in measurements taken in units of pennies are neither associative nor distributive, and transformations on measurements taken in units of pennies are neither additive nor multiplicative. Anyway, you mentioned you knew of at least 1000 units. I count 7. You have another 993?