p.1 #4 · p.1 #4 · camcorder that matches the d810?
Sounds to me like the OP is looking for a second camera (B Camera) that will closely match the D810's footage with the least amount of headaches in editing the two together? The OP needs to clarify.
most camcorders do not have sensors nearly as large as the D810 with the same range of depth and colour reproduction (without spending a S**T load of money)...... you will have a hard time matching the file off the camera without some post work. I use a Sony NEX5 and my D800 footage -- and have to do some matching in post. I use the D800 for video work, because I can do things like use my 14-24 which is stunningly wider than I could ever get on the NEX cam.
The D810 already shoots broadcast quality video (The TV show "Dexter" was actually shot with a D800 in the later seasons). The large FF sensor also has DOF that is not really matched by any Camcorders unless you want to shell out a ton of cash. It's going to look quite a bit different. I'd be surprised if you could find anything at all that is a direct match without post processing required.
You want a camcorder that mostly matches a D810... such is the price, rather than saying that they don't exist, which in the case of your $2,000 limit, they don't...