I am sure I could find something. I would do my homework. I would seek out companies that let me trial the products in my system to make sure they are what I am looking for. I cannot make any recommendations other than if I was looking to add features, such as vinyl, multiple sources, volume control, I would look for more of a full featured line stage.
I also, even in a bi-amp scenario, do not see why you would need almost zero output impedance? Depends on the destination components to a degree, and the load they present, sure. There are plenty of nice quiet tube preamps out there that have plenty low enough output impedance. Which is what the buffer would then turn into if you added all these features.
Maybe Dan can add all these things for you, I don't know, but I fail to see why some of your needs are actually important for your system. You might not find exactly the gain spec or the output impedance you are looking for, but within reason, you can get close.