http://freepats.zenvoid.org/Piano/
They sound very good. And yeah you could just use a soundfont player. But we want an .xrni right? Before I embark on my never ending quest of dragging and dropping 500ish samples, setting their keyzones and velocities, is there an easier way to do this than just manually?
You could try loading the soundfont in a vst plugin, then use the plugin grabber.
If the samples are conveniently sorted you can just drag and drop into the keyzones. If each sample covers one key you can also drag directly from windows explorer, which has more options for sorting the files. Remember you can also use the search function, it can make things easier if the different velocities has different prefix and so on.
I had a look at the files now and well…good luck! 
The sorting looks terrible and i wouldn’t even know where to put rel35.ogg or harmSA3.ogg or PedalD2.ogg. 
The rel samples are release samples, anddd yeah you’re right I have no idea where to put them. It’s going to take a while, but I’ll definitely post the results should I ever actually finish.