You're probably shit-out-of-luck trying to get it new; the DVDs have been out of print for about 18 months now, so the same is almost certainly true for any merchandise.

There's five scrolls... and that's the rarest.
I had to search three months to find it, but the shop is out of stock too.
Good luck!

http://animedoctor.com/harewasc2.html
http://www.animepavillion.com/catalog3.php?number=GE9490&seriesnum=H014

<--- Here's two other, but they're are unavailable too, i think.

I've tried both places posted, Anime Pavilion is actually a local place about 20 minutes from my home. I also keep checking ebay for it. It's just nowhere to be found, and I've been looking for a LONG time now. It's a little frustrating, if anyone on this board has one to sell I'd be interested in picking one up because I don't think I'll realistically see it again.

I got lucky and found this one in the local anime shop back when it was still around. Poster was pretty cheap, too.

Hey Cirno (or anybody intrested) if your still looking for one I'd be willing to part with mine . Go to cff.ssw.net/forum it's a haibane-renmei forum which I go frequently under the handle "logos", join it and send me a PM .