The subject has come up a few times and is also of interest to me............planning & thinking for now.
The hurdle is that most greeting cards makers haveca minimum run of 500 off though a few will do a split i.e. mixed qty of face images.
A new one I only recently found has very low/no minimum though the cost per card at suchow numbers is high but cards do retail for decent money.
They are called The Dandy Arthouse based in Yorkshire.
I have yet to check them out but as you have a ready customer see what you think???
Edit ~ of the ones I saw made by the above none were photo (all were artworks ~ I was at a gallery showing) but their website shows examples including photos. The other thing I noted and I don't know if all card makers do the same, was that on the reverse of the card it includes their own branding. In the past (a few years back) I did get a small batch made by Photobox ( just to test quality and for personal gifts) and they charged a premium to produce without their own branding!). Now, my thought is that as virtually every card in the shops has the manufacturers branding....... don't 'sweat it' as possibly looks more professional over a handmade card???