"That chip I referenced simply needs to be placed on the side of a pot of boiling water, and presto...you have voltage, but not much current"
No it does not , not for more than a few minutes.
You need to keep the other side of the chip cool, and that is the tricky part.
It can be achieved with water cooling or as in the case of the Bio with a fan, however if you had looked at the link to the prototypes you would have seen that many prototypes (read :loads of time and money...) have been built. You don't keep trying if you have a working one .

For the benefit of others, again I will point out that if you try it to do something like that yourself it isn't anywhere as easy or cheap as some try to tell you it is.
Franco