If you have a spare money and you want to invest in a company check HN everyday for "Review My Startup". Out of the few dozens that launch here every year, I am sure you can find a good investment (with enough due diligence).
The ideal version, I think, would be a way to invest a tiny amount, so you could diversify even a small (under $10k) investment. Even better, it could make it easier for a consultant to take stock in a small company as compensation, and could even make it plausible to grant stock in return for informal favors, introductions, etc.
I wonder if operating a shell corporation, with stock "accounts" controlled by individual members, would be a workable legal hack to achieve this. It would be fun to try and see.
I wish that were possible, it would be a great thing. However, what you are describing is essentially a public offering, and the listed companies would be subject to all of the associated regulation (SOX included).
The loans would be legal however. This kind of sucks - I can loan 5K to a startup, but I can't become a shareholder. There has got to be a way to 'hack' around this.
Why can't we call it a loan, but in the fine prints say that there is no guarantee to repay if the company goes bust. EDIT: And the loan is made to the Inc so if the companies fails, the owner credit will not be affected.