Regarding mp4 watch issue - I think these two improvements would mean much:
1. separate simple classic LCD screen for time and date which are visible always (instead of pushing button each time to see the time)
2. external changeable battery - because it would make watch much smaller without huge battery stuck inside (and you can detach the emptied battery and put charged one so you can use it longer), and since you need battery only when you want to use watch as mp4 player most time you would have a nice thin watch on your wrist. (there would be other, small, battery inside to power the clock at all times; and when you attach external battery the large screen would also show time)
But that reminded me of old SEIKO's tv watch:
It should look something like it - that's a great solution. External battery could be exactly in the place of that black thing on top of this watch.
SEIKO should try to make such watch.
It would have all the functions of these Chinese watches, and more (I really miss PDA functions - such as - MEMO, TO DO, CALENDAR, ALARM function, and also stop-watch would be nice add-on ...maybe even a calculator function. simply put: it shoud be a combination of full-function digital WATCH, MP4 player and PDA).
Of course it would be best if you could simply put programs into watch and run any one of them - any function you wish. It's a nice thing to have something like that on your wrist instead of carying things in your pockets - everything you need would be right there on your wrist.