The most obvious connection between the Happy Little Elves and a "real life" cartoon is to Peyo's "The Smurfs." The Smurfs, like the Elves tend to be good natured, kind creatures, and are, like the Smurfs, a funny color (elves being green; smurfs being blue.) If the Happy Little Elves aren't a parody of the Smurfs then are we supposed to believe that they are a totally original idea? This can't be the case, since it just wouldn't fit in with Itchy & Scratchy being a take-off on Tom and Jerry (the most obvious) and Krusty being a one of (substitute your favorite clown / variety show here).
So yet another suggestion for solving this problem is to turn to Walt Disney's "Snow White." We turn here for the simple reason that all of the dwarves (similar in connotation to "elves") have similar names, i.e. Grumpy, Happy, Dopey, etc. with an anomaly in Doc. The Elves are closely related, with Chilly, Moldy, Doofy and the anomaly Bubbles. Yendor is an elf we should look closer into, because as he stands, doesn't fit into this thesis. If we spell Yendor backwards, we get Rodney. Venture your own guess at this, but Rodney is similar in "ee" sound to the other elves/dwarves.
Pluto suggests that perhaps the elves are based upon those stop-motion animated Christmas films. Burl Ives has left his mark with Rudolph and Santa and.. none other than, the Elves.
Any suggestions to completing this theory should be sent to the OKH. Do you people not remember the Elves?