[http://www.appropedia.org/File_talk:Mechanical_Bike.jpg Discussion this is an answer to, since I can't edit that anymore
Yes, I' know about that, but the inherent problem is that a lot of those aren't designed to work with multiple attachments, many of them being built with only one attachment, from what I could find. And in many cases, there's no "standard" to speak of, but rather they're made "by the ear", to fit _some_ thing, but not much else.
But then again, this discussion is supposed to be about bikes, not about solving poverty, or ending racism and sexism, and things like that. Those things are also doable, it's just that people don't like to talk about those, especially in the third-world country called USA, which while might have the best prices for electronics and food, have extreme cases of corporatism when it comes to the prices of health and education, and the privatization of health, education and prisons doesn't help, since all of them want to get as much money out of people and the state as possible, while offering their clients as little usefulness as possible (as per the consumerist approach to life). And it's not like someone will suddenly start learning engineering and write a book with useful technologies and as little text needed to understand the text as possible (not necessarily writing less or no text, but offering graphics with little or no text, and a dictionary page with the words used and what they could refer to, in images), so that even the people who can't read would still be able to make use of those graphics, and so that one person able to read can explain them rather quickly how things work, and if that book would be small enough to fit in a (pants) pocket, then people are more likely to carry it on their person and check when they need to solve a problem.
I digress again. Sorry for taking your time. I'm just slightly frustrated that I cannot fix those problems alone, and I can't find the people trying to fix those problems and talk to them.