With the Spray attacks and Supplemental Actions already a part of the DFRPG rules, one effectively DOES have the capacity for multiple actions. They just require what may appear to be ridiculous skill penalties.
I've been gambling with the Fists/Guns skills of my enemy NPCs, using Spray attacks on all of the party members (bringing down each individual skill check to only +1 in the process), and they are still doing some damage to the party, and effectively increasing the tension.
So if you want to reflect a character's ability to perform multiple actions, boost the skills which come into play: either the primary attack, or any limiting Supplemental skills like Athletics. And also take Stunts which increase the skill rolls for applicable attacks/maneuvers/etc.
As for spending Refresh: I opt to use Refresh to lower the Time/Duration of a particular supernatural attack (1 Refresh to go from Full Round to Supplemental, or 2 Refresh to make it a Free Action).
Also, in the RAW, Stunts can be designed to decrease the Time/Duration of applicable noncombat skill rolls: how do folks feel about them making certain combat actions Supplemental or even Free?