I'm posting something a little different in the beam sabre category using the Gundam F91 (Jupiter Sanary experimental model) that I posted previously. I hope you enjoy it.
The beam shield that the F91 is equipped with is, as the name suggests, a shield that deploys beams, and can defend against beams and bullets. However, the part that's of interest here is the part that deploys them with beams. Simply put, it deploys beam sabers over a wide area, so in other words...
It can be used as a beam sabre!! In fact, the F91 in the show is used against bugs, and in the Gundam F90 Cluster currently being serialized in Gundam Ace, it's used as a beam sabre.

The beam shield can be used like this! | リョウ・シーモ's Gunpla works