Yes it's pretty common, in specialysed shops for Doujinshi, you can find pretty much about anything, including Arashi (there were around 50 doujinshi for Arashi in the shop I searched), also the first one you liked is apparently from a famous artist, or it's very popular, because it was exposed as a showcase among 20 other doujinshi about really anything else (like Gundam and stuff), and it was twice the price of regular ones, so I guessed Arashi doujinshi must be common stuff.