I'm not of much help regarding the costume construction but I can say that I dig this idea! It sounds really cool/unique and still recognizable! I can't wait to see photos if you decide to do it!
Masamune Date - Sengoku Basara
Luxray (gijinka) - Pokémon
Souji Okita (SSL) - Hakuōki: Shinsengumi Kitan
*~Next con I'm attending~*
FIN Kitacon (1-2 March 2014)
SAT Keisuke Sannan - Hakuōki: Shinsengumi Kitan
SUN Gin Ichimaru - Bleach