EBAY usually has these from time-to-time, and pretty cheap at times as well. Also, have you called Insight?
Really, I've heard another member here got a tape switch from them. I'll throw one more hint your way on the pressure switch...Laser Devices DBAL-A (2) unit uses the same switch. You can call those guys and they would probably be happy to sell you one as well. laserdevices.com/infopage.asp?id=40090&view=1
Hope this helps.