I've only seen a few models of surveying tripods, but the ones that I did see didn't have locking legs. Their stability comes from points on the bottom of the tripod legs which you drive into the ground when setting up the tripod. I'd imagine driving three stakes into your floor at home wouldn't be optimal for you.

You could probably find a used astronomy tripod (used to hold a large telescope and then position it precisely) that's out of spec for astronomy use but that would hold your laptop just fine.