Yes, Premiere Pro can write 4K 10-bit DPX sequences. Currently Premiere Pro can import 10 or 16-bit DPX files, but all export 10-bit. Max bit depth controls the depth effects and other rendering will be processed at as part of the render.
Thanks Steve. So is there somewhere in the export settings where I tell it to export the DPX in 10-bit, or does it do that automatically for anything 2K or bigger? Like is that the default? I ask because for the HD DPX presets it specifically says they'll be 8bit, but for the 2K or bigger presets it doesn't say anything. Here's a link to a screenshot of what I'm looking at: http://imageshack.com/scaled/large/405/hxqj.jpg
Likewise, if I use custom settings, like when I'm exporting for television UHD at 3840x2160, which isn't an option in Premiere's DPX presets, does that automatically export at 10-bit?
There are no export settings, Premiere Pro currently writes all DPX files at 10-bit.