I'm also not sure as to how much such an extension would be wishful in the context of Wine itself or if it would unnecessarily complicate the existing Wine architecture. Maybe someone with more insigth into NTDLL and its supposed architecture could explain more here?
I'm currently working on this by moving all device & file handling into ntdll. You'll be able (in the future...) to 1/ define your own new devices 2/ define the link of those devices to real unix devices 3/ handle the NtDeviceIoControlFile messages to the device type you're implementing.
(if everything goes as expected) A+