stylianos
In the Eastern Orthodoxy Stylianos was born to a poor family and became a hermit at a young age.  Unlike what we think of when we think hermit, Stylianos did not keep completely to himself, rather ventured out to the nearby villages.  It is said that one evening the Holy Spirit came to him and the next day he layed hands on a sick child who recovered immediately.  From this his notoriety spread and many came to him to be healed, but not just of physical ailments.  Parents would bring there children to him to give them spiritual guidance.  This over time lead to children being left with him for long periods, causing writers of the Eastern Orthodox to say he had started the first “Day Care”.

Also attributed to Saint Stylianos was the miracle of causing a barren women to become fertile again.  A women who helped in his work with children but could not have one herself became pregnant.  This caused her husband to tell this tale to others, barren women would then come to him to be cured as well.

Even though he was born into poverty and was a hermit, he was best known (other then his work with children) for his ever present smile.  I found two references to the only time he did not smile was when a someone of little face would try and discredit him then a scowl would cross his face.  Even when he was buried it was said he still had a smile on his face.

In my opinion he seems like very good inspiration for the Santa Clause of Christmas.  I do know there is a St Nicolas and have to reread what has been said about him, but a man who lived to be very old, was a hermit, had many small children around him (see this as more the elfs at the North Pole), was known to be happy all the time and cared for children.  I am sure I am not the first to draw these comparisons but having done little research do not have any to point to.

Wiki:
http://en.wikipedia.org/wiki/Stylianos_of_Paphlagonia

Additional links:
http://www.mit.edu:8001/activities/ocf/stylianos.html
http://www.orthodoxchristian.info/pages/st_stylianos.htm
http://www.newsfinder.org/site/more/stylianos_the_hermit/