Dex-based character with Two Weapon Fighting, Weapon Focus (scimitar) and Scimitar Dance and Dex 21 will, on a missed attack with his scimitar main weapon, deal 5+2+1 = 8 points of damage. I don't know if a magic weapon's enhancement bonus would factor in, but if it does the damage at those levels (minimum 11) would be 11.
It was mentioned earlier in this thread that this doesn't work, though not completely explained why, but here is the reason:
Most bonuses to damage (such as Weapon Focus, Two-Weapon Fighting, and Enhancement Bonuses) are specifically bonuses to damage rolls. (See the text for each feat, magic weapons, etc - they all use the term "damage rolls".) As such, they don't add to static damage amounts, like that dealt by Scimitar Dance.
The PHB, on page 276, also uses similar terms - various bonuses might apply to Damage Rolls, but there is no indication they apply to static damage from other effects. I believe there is even a specific clause to this effect somewhere in the Combat section, though I don't seem to be able to locate it at the moment.
Edit: Aha - just found it on page 57 of the PHB: "Some powers add modifiers to attack rolls or damage rolls. These modifiers apply to any roll of the dice, but not to ongoing damage or other static, nonvariable effects."