Cellophone
The cellophone is one of the rarest and least-known competition bugles in G, made by DEG Dynasty in 1984. It is really just a flugabone in G, and was based on Dynasty’s B-flat flugabone (which they called a “Marching Trombone”), itself a derivation of the original King 1130 flugabone.
The principal production run of the cellophone was a single group of four 2-valve instruments, built for and used briefly by the Phantom Regiment drum and bugle corps. No further 2-valve cellophones were built.
However, there are currently also four known 3-valve cellophones, which were presumably made for the European market. It is possible that the known four are the only ones that were made, but that is not certain.
Currently, two 2-valves and two 3-valves are in the hands of G bugle collectors and probably will not change hands anytime soon (if ever). The third known 3-valve cellophone is played by its owner in the Florida Brass, and the fourth has been lingering on Facebook Marketplace (as the seller will only trade, not sell) for awhile now. This leaves two known 2-valve models unaccounted for.
If you really want a cellophone, the easy way would be to get a normal B-flat flugabone and add tubing to get it down to G (as this is what Dynasty did). For the 2-valve cellophone experience, you could even just clamp down the 3rd valve and tune the first two valves appropriately. Dynasty flugabones rarely show up for sale (and the King flugabone pattern is not the only model of Dynasty marching trombone out there!), but fortunately there are quite a few King 1130s floating around. The King is likely the better instrument, but a less authentic base for a cellophone.
I have not played or heard a cellophone myself, so I can’t comment on the sound or how it compares to my King flugabone. But based on how B-flat marching baritones compare to the ones in G, I can’t imagine it’s a huge difference.