[patall]

Easier is the wrong word, you cannot just at a second pair of legs to a human as you would think from mechanical thinking. If you really want humans to live there you might have brains contained in an artifical container but adding some functionality to a complex organic system is hard, really hard. We may be able to do that in bacteria or yeast (and there these are billion dollar projects like the next-fuel incentives) but are not in multi-cellular organisms. Too many levels of control you have to cover, you do not only have to manage the status quo but also the embrional development and managment over 90+ years. And this with-out trials, at least if you are against human trials which would be massive and lead to thousand of dead trial persons. (I mean we are not able to do this in mice and even there every trial faces massive ethical opposition). Maybe in a hundred years (but who knows what will exist in a hundred years), everything else is blatant optimism.