Overview
If you follow the anime, you would know that Shoutmon DX (Double X) is a combine version of ZekeGreymon and OmniShoutmon (OmegaShoutmon should be a LV6 red digimon that will be released in this BT5-Battle of Omega). The Shoutmon appears in Red color, provides red a better strategy and power that people now compares it with Chaosmon.
Combo to play with Shoutmon DX
By looking at its effect, we are 100% sure that Shoutmon deck would use [BT5-017] ZekeGreymon and [BT5-014] OmegaShoutmon. The ZekeGreymon in Shoutmon DX digivolution source, using its inheritable effect, ShoutmonDX can even attack unsuspended digimon in its turn when it digivolve, and OmegaShoutmon give "SecurityAttack+1" for this digimon. On top of that, If we put more OmegaShoutmon or ZekeGreymon under its digivolution cards, it can delete opponent's digimon that has 5000DP or less. By the way, Shoutmon DX has only 12000DP, not high enough to be able to attack other LV7 digimon, so we have to boost it up with option card or inheritable effect from its evolution source digimon.
These below digimon and option cards are useful for Shoutmon DX deck.
When forming strategy for this deck, it reminds me of Lengend-Arms Ragnaloardmon deck. There is a LV3 digimon that helps to check top deck and put to hand digimon with "Greymon" or "Omegamon" in its name, it is a new digimon in BT5 [BT5-007] Agumon. The LV4 digimon [BT5-010] Greymon gives +2000DP in its inheritable effect. This effect applies for ZekeGreymon, OmniShoutmon and Omnimon (BT1 Omegamon) but not Shoutmon-DX. Also, there is another LV3 [BT5-009] Shoutmon to reveal 5 cards from top of the deck and then take 1 digimon with "shoutmon" in its name and a digimon with "blitz". This card helps to draw "Shoutmon" or ZekeGreymon or BT5 Omnimon faster.
It would be more scary if we put LV7 [BT1-084] Omegamon (Omnimon) for Shoutmon deck. For normal digivolution source for Omegamon, we only have 1 LV6 digimon to remove to make Omegamon active again after its first attacking, but if Omegamon is digivolved from Shoutmon-DX, we don't know how many LV6 digimon will be there, can be more than one. You can count it to make Omegamon active time as the same number of LV6 digimon. If the combo comes with [BT5-084]Omnimon, the inheritable effect from OmniShoutmon still able to be in used. When digivolving, he can unsuspend itself, do 2 security check and if we have 2 LV6 under BT5 Omnimon digivolution source, it can avoid returning this card to hand/deck or other option card effect twice (for normal digimon attack, we can use blocker to block). The ability of "blitz" is going to make red even faster than before.
I also would like to recommend [BT3-016] Durandamon to be included in this deck. First of all, its play cost is only 10, can be definitely useful for Megazoo deck with Shoutmon-DX. Durandamon also give "Piercing", so if we digivolve Shoutmon-DX from this LV6 digimon for 2 cost, put ZekeGreymon under its digivolution card, Shoutmon-DX can attack unsuspended digimon and with piercing, it can check 1 security.