Yes, a special attacking Blaziken is possible, but it is less effective than a physical attacking Blaziken, in my opinion. Either way, here's a special attacking Blaziken set I created on Pokemon Showdown:
Blaziken @ Leftovers/Blazikenite
Ability: Speed Boost (If possible)
EVs: 252 SpA / 4 SpD / 252 Spe
IVs: 0 Atk
- Focus Blast
- Vacuum Wave/Will-O-Wisp
In terms of moveset for a special Blaziken, there aren't many options. If you're using an in game team, I think it'd be easier for you to just try and replace Vacuum Wave with any filler move you want, like Will-O-Wisp, since you have to have a Generation 4 Blaziken to get it to learn Vacuum Wave.
EDIT: My bad, you can't have Vacuum Wave on a Speed Boost Blaziken, unless you mega evolve it. Good luck on your special attack team!
Hope I helped! :)