The main shortcoming, in terms of durability, of pocket watches were water resistance and lack of shock protection. Both of these are easily solved now with screw together cases, gaskets, and antishock devices.
As others have said, Tissot makes pocket watches that pretty much fit the bill.
One thing I don't think I've seen on modern pocket watches which I think would be interesting if you wanted to up the resisyance a bit would be a screw down crown. You also rarely see them in steel cases. But, this could easily be done. Take basically any modern ETA/Unitas cal 6497/6498 based watch design, delete ths lugs, add a threaded case tube and screw down crown, add a suspension bow, and you'd have a burly modern pocket watch.