One of the staples of D&D early on was the Flask of Oil used as a weapon.
I always wondered why it was never included in DDO (scratches head at Spears still missing from game too). But we have something like it in the Sun Flask. Why not use the exact coding for a Sun Flask but simply change the damage from Light to Fire. Problem solved. Put them up for sale at every General Vendor and viola! A classic D&D item is easily added to the game.