It could be done with text, yes, thus my suspicion that this would be a very simple thing to do. But I'm hoping for something like a web app that anyone can install on their web server, that allows issuers to easily set up stock IPOs, the investors can do initial purchases at automatically (purchase with BTC, that addy gets registered automatically), and users can send change announcements to. For example, "log in" by entering your BTC address and signing a provided message, to see that address's holdings and other information; and use some sort of standardized POST commands to request changes, like [BTC address; CHANGEOWNER "new BTC address"; signature], which if standardized can be sent from anywhere, thus allowing third party exchanges go send requests to various distributed company ledgers. So, ideally this would be a plug-and-play package, maybe open source, with some agreed upon standards, and will, in a sense, distribute all stock issuing authority to the final points of failure, those being the actual companies themselves.

The colored Bitcoin idea sounds interesting, as long as it exists alongside Bitcoin, not as a part of it, but, again, it may be overkill for a whole new block chain just for this. It would work well for other types of contracts, but if the stocks are distributed, but the company is not, that distributed colored Bitcoin stock won't help any if the company is shut down.

As for scams, at least until some third party central exchange gets started, if you wish to invest in a company IPO, you would actually have to go to the company page directly. Hopefully that means that you will have to do some actual research and see what they offer, in head of just get a brief description of financials and expected returns. Hopefully this also means that companies will have to do some heavy promotion and advertising to get their awareness out, since they would have to get people to come to their site, as opposed to some fly-by-night scams simply registering on an exchange with minimum of info, and running off as soon as they get enough gullible investors.

Regarding #assets-otc, that's close, but, again, it's another centralized point of failure. Also, why stick with PGP keys? We can sign with BTC addresses, and BTC addresses are all that is needed to receive IPO purchases and distribute dividends. PGP keys seem like a redundant extra layer, since you would still need to register a BTC address alongside it to receive dividend payments, and since to use PGP you need to install separate PGP software and learn how to create, use, and backup PGP keys, while BTC address signing is already available in many BTC wallets.

The train of thought I'm operating on nowadays is decentralize EVERYTHING.