But it'd take a sophisticated program to do it, and I don't think you could buy it at Best Buy or Walmart. That's something that'd have to be made from scratch. It wouldn't be impossible tho'. You'd need someone who knows how to program computers.
The program has to watch the date and time, and then have each email cataloged to send off at a specific time. How'd you accomplish that, you'd have to ask the programmer. But it sounds cool.....devious, actually.
Don't think that's possible. You could compose them ahead of time and save them as drafts. Then, if you have web access during your travels just sign into your account and send the drafts as often as you wish.