Another two tips for skinny dudes that want shirts: J Crew and Club Monaco. If the sleeves are too long, ask your dry cleaner or tailor to shorten them for you.
Absolutely. I wear dress shirts on a daily basis and whenever J.Crew Factory has a good 40% off sale I buy six of them and just get the sleeves shortened. It's one of the easiest alterations out there and only costs about five bucks a shirt.