Could someone kindly give a status update on when will we have a real-world, usable CoinJoin (besides the implementation on Blockchain.info)? This thread is huge, and I'm sure many casual readers would like to see a tl;dr to learn will this result in a usable client soon, or what's the plan?

I found the thread when reading this article from 7 months ago. What has happened since?
http://bitcoinmagazine.com/6630/trustless-bitcoin-anonymity-here-at-last/

damn that was fast. well glad thats out of the way. So you're not selling any more?

Here is what I feel will happens roughly :

if (JRprice == x)
{
     masterXchangePrice = x - 10%;
}

In my humble opinion, trading OTC will impact the market more than trading quietly on an exchange.

First, all trades impact the quantities available in the same way, if you sell 1000 MSC OTC, that will always be 1000 MSC that wont be bought on the market. There is no "if you dont trade on the exchange the price will not be impacted !".
Thats an economical fallacy; the price converges to the same value everywhere and the exchange is a part of the market in the same way that the OTC is.

Second, saying that you have X quantities to sell at Y prices is much worse than trading them little by little : As long as the market expect a bigger quantity to be traded, the price will correct itself until the price discovery process is finished. Thats like bill gates announcing that he will sell 1% of MSFT the next week. What huge holders are doing is that they pay brokers to liquidate the quantities as quietly as possible on the marketplaces.

Having said all that, I will add that this is only an opinion and that its really great that JR is commiting himself to Mastercoin full time

This is all fascinating to follow in term of economic theory

If user A sends (prefunds) MSC, and user B sends BTC, what part of the trade requires the use of Bitpay?

We are a payment gateway not intended for the use of exchanging cash or cash equivalents. The sale/exchange of currencies using our services is not permitted.

I suggest that we ask maaku if he’d get on board. maaku is an experienced Bitcoin developer, who has been (?) working an a project somewhat similar to Mastercoin (Freimarkets), but which didn't get crowd‐funded as he hoped. maaku has been earning money from community donations, etc., and I expect that he'd strongly consider filling a salaried position as a Mastercoin developer. See his Github account.

We also might consider Vitalik Buterin (who wrote Pybitcointools and has demonstrated in interest in Mastercoin) and/or one/more of the other Dark Wallet devs—that project has only raised about $100k, so they can't all be working on it full-time.

In any case, we do need to be looking outside of the Mastercoin project for developers: Tachikoma and zathras have repeatedly stated that they're not for hire (though I would support hiring Bitoy, grazcoin and/or rbdrbd); we have thousands of bitcoins in the bank and a very cool project—we shouldn't be begging for time commitments.

The new opportunity is in businesses that deal with bitcoins. The right ones will see just as much appreciation as bitcoin did. Bitcoin will enable a new economy and you're in at a very early stage.