As hard as it is to find any service manual at all for old machinery, and then when you spend $100 to order a used manual off ebay find that the really useful pages are ripped out or covered with grease, I think a product like you describe is waiting on AGI more than it's waiting on nice AR glasses. Very few people need this product, so the intellectual labor to produce it will need to be nearly free.
I've gotten to where I can identify most bolt head sizes on sight... I very rarely have to pick up more than two wrenches and usually the first one is right. Also I find that bolt sizes are typically fairly standardized on a particular machine. I occasionally work on a mini-excavator that has 10mm, 13mm, and 19mm bolts (and 8mm allen-heads), but nothing else I've found so far.
Well I haven't worked on anything with JIS! A guy I used to work with hadn't had fractions in school, so he would use the metric even on SAE parts. He couldn't figure out that e.g. 7/16" is smaller than 1/2".
I've gotten to where I can identify most bolt head sizes on sight... I very rarely have to pick up more than two wrenches and usually the first one is right. Also I find that bolt sizes are typically fairly standardized on a particular machine. I occasionally work on a mini-excavator that has 10mm, 13mm, and 19mm bolts (and 8mm allen-heads), but nothing else I've found so far.