You can make a DIY version of the cheaper models that OP linked to. But without the body vest thing, I would imagine your arms would get tired very fast.
I just made a shoulder mount out of pvc, just need to get some pvc cement to get it to stop creaking on me and I'll be good to go. It's not perfect, but it gets rid of at least 75%(I'm being conservative here) of shakyness when moving. Panning from a or holding at a standstill is even better results. I'm trying to come up with a design to make a support (still out of pvc) that is hands free (thinking about doing over both shoulders, with two pvc 'straps' horizontally in front and the actual camera support in the middleish and attatched to both horizontal bars). It'll be a lot of trial and error, but good thing pvc is cheap!