Absolutely, a mousse ganache would just be relatively thicker than the base ganache that made it, but lighter once set. It should be pipable without difficulty, in fact, I'm sure that's how they make several truffles, just instead of piping them in shells, they pipe out rounds to coat in chocolate. Pleasant in a shell, for sure. Even without a guitar, give making it a try, just try putting on a chocolate "foot", then flip it and cut with a knife dipped in warm water, then wiped dry between cuts. You can get great results, it just takes longer :-)
