A possible option might be using Carbon Copy Cloner with an external drive. This will give you an exact copy of your internal drive and possibly allow you to remove the apps you are not using on a regular basis from your internal drive. You could then boot from the external drive with CCC and run the apps from it.
But as Fishrrman stated, be careful and slow about doing it so as to not mess anything up. Have never tried it myself. Maybe someone on the boards has and can add further info to assist to with it.