Good suggestion Steve. In the most recent release of FabMo (1.7.0) it looks like the job delete process is pretty quick (clicking the trashcan button on jobs in the queue--However, I'd have to check more thoroughly to see how job size affects delete time.
Slightly off topic--but I did a similar study for job load-time last week and found some interesting things. The Edison seems to be able to parse 10,000 lines of code per second. So a 200,000 line job will require 20 seconds of parsing, plus 5 seconds of initialization = 25 seconds to start the file. Just a little thing I'd always been curious about--some jobs can get up to 1million lines for 3D carving...so it can seem pretty slow to start. There should be a limit at which the file can start before parsing all lines of code--but that isn't what is happening currently. Will be trying to get that running faster in future versions!