They also combined Thor (also often written Tor) with other names to create names like Torbjørn, Torstein, Tormod, Torvald, Torgrim etc. The same goes for female names, where Tora would be prolonged to make Torbjørg, Tordis etc.
For some reason I have never heard of a name that combines Odin and something else. Maybe the explanation of one syllable is correct.
All these names are in use in Norway today, although maybe not for babies at the moment (typical grandparents' names).