The real question is if you want to accurately clone "vintage gear" or if you want to have something modern which is only somewhat "inspired" by "vintage gear". If you really want to create an accurate clone, sure, this is hard and potentially not that cheap, since it might require multiple hardware revisions before you're satisfied with the result. But if you only want to build something similar, which obviously won't sound exactly the same as the "vintage gear", then it's cheap and easy to do. Also keep in mind that you totally can get e.g. 8bit DACs or 12bit DACs if you really want. Even with "variable sample rate", like what some old digital samplers did. If you then play around with different interpolation algorithms, because modern microcontrollers are fast enough to allow you to do this, you'll get a sound that's surprisingly similar to "vintage digital gear". Sure, it won't be e.g. an E-MU Emulator, but does it really have to be one?