Special thanks to nostalgiateenable's YouTube page for posting The Hub's Fraggle Rock-A-Thon Promo. While not the actual promo, it was recorded live from the TV during a commercial break. Still looks and sounds great to me!
The Hub's Fraggle Rock-A-Thon promo starred Gobo and Red, and YES Gobo speaks and the new performer has him sounding amazing.
Matt Vogel, who has done many of Jerry Nelson's characters, has confirmed to me that it is not him performing Gobo in this promo spot.
Update: Thanks to Jesse Oliver who found out that, John Tartaglia performed Gobo in this promo. Great job John!