I don't think market makers are a solution to the problem you see. Market making might reduce some liquidity spikes, but it wont stop the big price swings. First of all, the function of a market maker is to provide liquidity and reduce the bid/ask spread. Second, a market maker has to be nimble. A market maker that tries to block price swings by putting up big walls is just going to lose a lot of money.
A market maker with a lot of bitcoins can MAKE a lot of money by putting up walls to prevent the price from changing too fast. Consider what I'm doing with my meager stash of bitcoins, then imagine what would happen if someone with 1000 times as many bitcoins did similar.
The price around $145 as I write this. I currently have buy orders for 0.5 bitcoins at every $1 increment from $100 to $141. I have sell orders for 0.5 bitcoins at every $1 increment from $145 to $200. Whenever one of my buy orders executes, I immediately place a sell order $3 higher. Whenever a sell order executes, I immediately place a buy order $3 lower. As long as the trading range stays between $100 and $200, I make $1.50 (after commissions) on every buy/sell pair. If it goes outside of this range, I wait for it to return. History says it will return.
I haven't been trading this method for long, but it looks like I could average at least $5 per day, or $1825 per year, on an investment currently worth about $7200. That's 25% return on investment per year. Might turn out to be more.
Now imagine the effect someone with 10,000 times as many bitcoins, putting 100 BTC buy and sell walls at every $1 increment from $10 to $1000. They would probably not make nearly the same return, because their action would dramatically reduce the volatility. That would ruin things for us day traders, but would make Bitcoin a viable alternative for housewives in Argentina, which is awesome because it makes my "buy and hold" stash MUCH more valuable!