Scarab + Dune scorpion is not a rush deck; it is a stall. Scarabs are not rushing cards because their damage:cost ratio is poor, especially for such a cheap card. Scarabs are instead used as a combination between CC and damage in order to deal damage while staying alive yourself. Dune scorpions are the ultimate attacker for non-deckout stalls, and rather weak in rushes. Their damage they deal a turn (poison) will, on average, increase every turn. This means they are fantastic in decks that take many turns to win, stalls.
I like the awkward rush idea, TII, but be sure to include shields.