Awww, Sakina, you're making me blush! I (nor my hair) aren't that great, but thank you!
I'm sure your braided bun must look really nice! As for me, sometimes when I do a Dutch classic, the bun portion resembles a danish. *lol*
Using kanzashi with your wig sounds like a good idea. As for getting one in person, my brain isn't working very well at the moment. Did you want to get a kanzashi from Maya Kanzashi while you were in Japan or just a kanzashi in general? If it's the former, I'll go to their website and see if they have physical shop you could visit.
At any rate, I'm guessing you're going to be at Narita Airport (aka New Tokyo International Airport), which is about 35 miles away from central Tokyo and takes at least an hour to get there. That kind of rules out Tokyo -- too bad your layover wasn't longer! -- but if you do manage to get there here's a couple of places that might carry kanzashi:
-Oriental Bazaar in Jingumae, which is in western Tokyo
-Nakamise-dori in front of Senso-ji temple in northern Tokyo. It's a series of shops that leads up to this huge Buddhist(?) temple
Japan Guide has an article on Narita Airport and directions on how to get to Tokyo. I'll look at my Japan guidebook again and look for a couple of Tokyo deparment stores you might want to try. Almost forgot,
Narita Airport has some shops you could visit in case you can't get out of the terminal. I don't know if they'll have kanzashi, but it wouldn't hurt to look.
But, because of time constraints, it might be easier to catch a bus or something to Narita city and go to Sun (or it might be San) Plaza Shopping Center. According to a 2nd hand kimono directory I have, there's supposed to be a kimono store there. However, the directory is three years old so the store might have closed. Then again, there might be a different one taking it's place. Ack, sorry that wasn't of more help.
I haven't bought from Maya Kanzashi, mostly because I don't have the money. *sob* Ebay sometimes has nice kanzashi (though not as nice as Maya) for way less.
Good luck! I hope you find something you like.
Hair--I think I have go back to washing my hair every four days. It's getting rather hot now and today I noticed my hair had a gross, sebumy smell to it. I tried the Nature's Gate shampoo and so far I like it. And...yeah.