I concur on the "no personalization" thing. I have never seen this available at DLR. They only have one dedicated Christmas shop at DL, in New Orleans Square, but it is a teeny tiny shop, and there is not an area where they do personalization, unlike at the shop at WDW's Downtown Disney, for example.
However, there is NO shortage of Mickey Head christmas ornaments. They are everywhere during the holidays. You should have no trouble finding some more.
INTERCOT Staff: Disneyland Resort-California, The Water Cooler
Wilderness Lodge Aug. 7-15