Here, in no particular order, are some leads:
This is a US based one called BookBaby (it's a self publishing one)
That seems to be good for online publishing
I got their details at the London Book Fair. (I've got a massive list of contacts from them, which I can share later)
One thing you may want to do is contact Nielsens to register your own ISBNs (You have to buy them in batches of ten) if you are intending to create more than one.
Damnit. I can't remember the other stuff off the top of my head but I have tons of info on this
One thing I would say. Don't use a vanity publisher. They will build up your promises, bill up your bank account and break your heart.
If anyone makes a sales projection that sounds too good to be true, it certainly is.
Everyone loses their marbles when it comes to their book babies. (Unsurprisingly, since these are our emotions being poured out onto the page)
There are many people who will exploit you.
Hold on, once I find the other contacts I'll post them up.
Just don't sign anything rash!