Website:
http://pajamapress.ca/
Their staff seems to have a lot of experience and their books have won multiple awards, according to the website. I'm pretty sure I've seen their books in Barnes & Noble, too, which means they have a good marketing and distribution network. Their covers look great. I've never read their books, so I can't vouch for the editing, but it's probably top notch.
It looks like they accept queries, but you would probably have a better chance with an agent. Good luck!