You certainly could ask a doctor for a low dose of Lunesta or Ambien, but they very well may turn you down or at most only give you a few pills if you say you're only using it on vacation. Also don't be tempted to take any medication that like from a friend to take with you or try to take it through security without a prescription bottle with your name on it. I'm not sure about Lunesta, but Ambien is a controlled substance. It's in a class of drugs called benzodiazipines (what Janice Dickenson is/was addicted to for anyone that watched Celebrity Rehab). It's a hyponotic sedative. I have very very very bad insomnia and take the maximum prescribable dose every night. I've taken it for 3 or 4 years now. I'm only going on about it because anyone taking it should realize it isn't something to play around with, it is a full on drug. Also not everyone reacts the same way to it. When I first started taking it, I fell asleep in 20 minutes, which since I was used to laying in bed for hours before sleeping even with the other med I was on, was great. Now it takes me about an hour and a half to fall asleep, since I've built up such a tolerance to it. If you read the warnings that come with it, you'll find that Ambien can make you very dizzy, it can cause hallucinations, and it can make you sleepwalk among other things. Also after any type of repetitive use, it can cause withdrawl. If you only take a small dose for a short period of time you'd probably be fine, for me to stop it cold turkey I'd be one very sick little lady

. You also really need to have the time to get 7-8 hours sleep like the commercials say. If I only get like 6 1/2 or 7 hours sleep, I feel nauseous the next day. You can also end up being very uncoordinated and drowsy, almost like a cough syrup "high" if you don't sleep enough with it. Just stuff to keep in mind.
I was very worried about falling asleep on the trip I just got back from, because the previous two trips, I ended up being awake from Sunday afternoon to Tuesday night. Yes you read that right. The last time I was awake for 52 hours, and let me tell you that doesn't feel very good. I always fly out on a Monday morning, so lets call them trips 1 and 2, I'd gotten up Sunday afternoon (I used to fall asleep around 4 am and get up about 1), packed, knew I had to get up early so I didn't take the Ambien, knowing I wouldn't be able to get enough sleep, so I was up Sunday into Monday, tried to sleep on the plane...didn't....tried to nap at the hotel...couldn't....came back from dinner and took the pill...and nothing. Did the front half of Epcot Tuesday and finally, each time, I'd finally be exhausted enough Tuesday night that I'd fall asleep. So needless to say, this time I figured that would happen again. I was up all night Sunday into Monday, as I expected, but since this time I was in a 1 bedroom villa at OKW rather than a normal room at POP, I sat in the jacuzzi for awhile figuring it'd help me relax, then I got out, took the Ambien and my other stuff and laid down to read, 20 minutes later and I was out. It was great. I ended up sleeping really well this past vacation and it was amazing, I was falling asleep within half an hour of laying down which just doesn't happen for me at home.
Anyway, I feel your pain, and I agree with a lot of the other posters suggestions. I can't vouch for how they work because they never worked for me but I'm a pretty extreme case. I just urge you and anyone that can get a script for Ambien to take it seriously and be cautious and aware with it.