Andrew,
Don't waste your time with the jigsaw. That will just make a mess and you will end up with a tacky looking job.
As the others have recommended, either use a laminate trimmer or a flush trim bit in a router.
If you can't wait till fathers day, take your dob rocker box to a local kitchen refit company and ask if they can run a laminate trimmer around your base. It will probably cosy you less than $10. I have 5 companies I could go to within a 5km radius of my home. But then I also own a router with several flush trim bits
CS-John B