No, it isn't. As others have mentioned, most HN readers and YC founders are not (yet) wealthy enough to be accredited investors. If you were to try to treat it simply, you would wind up in serious legal trouble, and possibly in prison. Selling shares to any non-accredited investor, who is not a founder, requires dealing with a lot of legal issues, and potentially opening yourself up to significant liability.

The side effect of this law intended to protect people is that the average person can no longer participate in the highest growth sectors of the market. The rich get richer, and the poor don't have as much choice in their investments (and once a company has gone public, its astronomical growth is probably over; it's very rare for a company to be as successful as GOOG or AAPL, and even those, if you'd owned stock pre-IPO, you'd be incredibly wealthy today).

I would love to be able to invest in some of the YC companies, other than my own, but I don't have that ability yet. But, the first few rounds of YC companies have produced some accredited investors already, so the circle of available investors who "get YC" is getting wider.

You could get a personal loan from friends and family, and then roll the money into the business, but you can't sell shares without dealing with the extra paperwork and liability.