The issue with galvo C02's, as I see it, is the power to speed ratio. I have 4 C02 lasers- a 30w, a 40w, a 35w tested at 47w, and an 80w; and I have 3 30w galvo fibers...
My 30w machine, to produce engraving
to my liking on black Rowmark requires no more than 75% of its 80 inch per second speed at 100% power and 500 lines per inch resolution-
My 40w machine I run at 85% of its 80 inch per second speed, etc,
My 47w machine runs at 65% POWER at 100% of its 80 inch per second speed,
My 80w machine's max 'decent engraving' speed is a whopping 27.6 inches (700mm) per second, so it doesn't even count in this conversation!
My 30 and 40 watt machines are 14 and 15 years old and running their original tubes, so I'm suspecting their actual output is around 3 or 4 watts less than 'advertised', which is backed up by my 47 watt machine requiring a reduction in power rather than speed to produce the same results...
That all said, assuming a 60w laser at 80 inches per second would likely run at 50% power, then a 120w laser should give good results at 160 inches per second--
But a galvo head is capable of 300 to 400 inches per second engraving speeds. Which means to get real-world use of that speed would require at LEAST a 100 watts of power, just to engrave Rowmark. With that much power I believe a galvo C02 would be a viable piece of equipment, with the caveat being the output size limitations, 8x8" work area with a 200mm lens, etc...
so after I typed all the above, I checked out the video Art posted up-- a few observations: I noticed, and this is just guessing based on what I saw, that the laser is running that wood at around 20" per second- maybe a bit faster but not much. However, vs a gantry machine, it's an exponentially more efficient 20" per second since a galvo passes over all 'white space' at full speed. But I did notice a strange anomaly, a great deal of waiting time between laser stops and starts at times... that just doesn't happen with my fiber machines, any time gaps between jumps are in the milliseconds. Pretty cool to watch! My BIL engraves almost nothing BUT wood, one of these machines is probably in his future!