Ward and I have been discussing this idea in another thread that I now can’t find (it might have been in an auto-deleting announcement thread) … From our latest exchange in All Streets or All Nodes? - #78 by ward_muylaert I think I’ve got a process that could accomplish this by adding nodes every e.g. 25 meters (or whatever distance I land at). I need to test things, somehow, to determine how much more space this will require in my database. 
It probably would have been impossible with the existing city sync process. I’ve spent the last few weeks rebuilding that, though, which has opened up some other possibilities. I’m about to start testing things in the live site. I don’t expect to make meaningful progress with that until next week, though. I also won’t be looking into the ‘add more nodes’ possibilities until after the city sync process is fully replaced, just to keep things simpler each step of the way.
The half-correctness of this is what allowed me space to accomplish it…
While there isn’t a concept of “street” in OSM, there are Ways … and those ways have a collection of ordered nodes … which, with the right tools, can be combined into linestrings and manipulated at the database level.