Copper is the only other 4 Combo Mutation. It appeared in the 1970s and is very sought after, yet rare due to both the rarity of the Rust (bb) gene that's used and also the sheer number of mutations used to create it. [1]
Copper |
U_eebbpp |
References
[1] Logsdail, C., Logsdail, P. and Hovers, K. (2007). Hamsterlopaedia. Surrey [England]: Ringpress, p.133.