Successfully replaced the shaft in a 5015 blower with a longer one for spinning the portal fluid animation bits.  

I started with an old processor fan.

Destroyed that one attempting to remove the shaft.  I didn't support the plastic while trying to pull the shaft out and... snap.

The only other fan of appropriate dimensions I had on hand was a banged up 5015 blower with the wires and the positive pad on the pcb missing.  Once I found where to inject power, it still worked.  I nearly smoked it hooking it up backwards at first and think I may have burned out the RPM feedback.  Oops.

The shaft is still quite overly long atm.  I'll cut it down once I have that dimension fixed.