Industry conferences that include competitions among scores of startups generally don't look too kindly upon companies producing hardware. Nonetheless, there were quite a few physical products shown off this week at TechCrunch Disrupt in New York. These were either the main offering of companies or complements to their service offering, and judging by their demo platform of choice, the iPhone appears to be a leading agent of disruption -- the companies introducing hardware used Apple's handset to do everything from avoiding stress to measuring its biological impact. Switched On will introduce four such products after the break. CarKit by Getaround. Disrupt Cup winner Getaround is a peer-to-peer car rental competitor to Zipcar et al, and the vehicular counterpart to Airbnb. One way it hopes to get a leg up on its competitor RelayRides is with a user-installable CarKit that combines GPS, WiFi and a remote keyless entry solution. The idea is that prospective renters can unlock