Shashin... I wasn't saying there were objectives of 2000x. I said "It's not till you want 10x to 2000x that you need that kind of money".
I have several microscopes that do 2000x. This is easily accomplished with eyepieces and quite common.
On tube lenses, what about the objectives that were created for use without a tube lens? I have 40 or 50 of those myself. You really do get the full magnification they're marked at. I do when I shoot a scale at least. 4x for example shoots a 4.5mm to 5mm on my 18mm sensor. 18/4=4.5 so that's exactly correct. A 10x gets me almost 2mm and 18/10=1.8 so again, that's correct. That's using them at their proper registration distance (tube length) but you can also get more magnification out them (especially the ones marked infinity) by placing them on a bellows or tube which is longer than the tube length.
I think I recall a discussion in which it was revealed that objectives designed for a tube lens are extremely inferior because the TL does some corrections and without it ya end up with lots of CA. Also tube lenses exist for cameras - I have a couple - one for Minolta's MD mount and one for Olympus's OM mount.
You can call it a hack if you like but in the same way you can call just about every device made for photography a hack. Flash, extension tubes, filters, mount adapters, even a digital sensor itself is a hack of film. We live in a world of almost nothing but hacks. Cars to hack horses, hacked animals like horses to hack walking, and etc. etc.. The only thing we really need to care about is weather or not it works and how well.
The results for some purposes can actually be much better than a microscope - or even make possible that which is impossible with the limitations of a microscope.
Can you find the model name or a link to that Minolta lens you're talking about? I'd love to check it out!