Nah. Would make grinding too easy. Plus you would need to run the same deck in both anyway.
I'm not an expert on the matter, but I really doubt you can do all that with one deck even if you played them separately.
Which in turn would clash with the current scripting that only allows one deck at a time.
Next you'll argue that they should create the possibility of saving multiple decks at once to different game rooms.
Right now, since you can only play in one room there just isn't a reason to keep that many 'active decks'. And you can save the presets already and the dropdown menu is right there with the game client. That's as fast way to change between decks as you need unless they for some weird reason do follow through on your idea.
If they did that... You would find me playing in Deathmatch Extended, Deathmatch Extended 25, and Deathmatch Standard all at the same time, and leveling would be SO easy.