Might work, not sure how permeable wax is. The egg should be very sanitary after boiling though. I am doubtful the pressure cooking would be positive from a culinary point of view.
I am a big fan of 1000 year eggs in general. They are not particularly gross (one of those things where the idea or the name or the appearance is what is gross, not the actual flavor or texture). They can be a bit on the sulfury side but preparation can usually take care of that.
McGee has a procedure where you use a brine rather than the mud cake and the result is not excessively sulfury and the white is clear and the yolk is bright yellow (so, much better looking than normal). Been meaning to try that since I read On Food and Cooking a couple of years ago.