Hm. Sounds like colored coins have all the advantages of Bitcoin, plus lack of volatility.
Alas no. They have most of the advantages of bitcoin since they are still bitcoin in full. However, whatever additional value the 'color' grants to the coin over the base worth os a BTC is based on trust in a specific agent. They are nothing more than a promise from a supplier to redeem the coins into another form of value at some time in the future. It is a trade off. Convenience and stability purchased by requiring trust.
So if they existed then would we ditch regular Bitcoins for them?
The regular coins are still what are required to produce coloured coins (the name is really good analogy). Coloured coins being used more would seem to lower the expected price of uncoloured bitcoin, but they couldn't make uncouloured coins worthless since they themselves entail a demand for them.
How much software would need to be changed in order to implement colored coins?
It would mean taking the existing 'beta' implementations, making them stable and having people start to use them. Merchants accepting them automatically (and being able to tell they are worth more than uncouloured coins) would also require making improvements to whatever software it is that they use now.
The bitcoins that I had set aside for a Cryonics contest two years ago (and were unredeemed) are suddenly worth a lot more.
Details: I had added 10 bitcoins to get things started, and there were 4.75 worth of additional donations. These were partially lost when the hosted online wallet that I was using (MyBitcoin) was hacked, but 49% was recovered. As of today, after refunding part of the donated money, it is now worth 5.2675. I will be adding from my personal store to bring it up to an even 5.5. At $140 per coin, the new total is $770.
I've decided to follow the buy-and-hold strategy for at least another year, since it worked so well. I don't have exact details on what I'll do with it, but it will not be converted or spent for at least one year, and will eventually be used for promoting cryonics in some way.
Some things I have in mind if it gets big include:
Contributions can be made to:
1Jdn36JUwvJdr3Qiie4aAseFdcoTsND9Qo
(Updated, since the previous address was attached to my personal wallet on an outdated client, which was causing money to be moved out of it by accident. The above is a brainwallet with a reasonably secure passphrase, generated using Blockchain.info.)