I don't think it will be that quick, but look at the Wii. eBay Wii and see how many hits you get. How many are selling for $100-$250 OVER retail? Why? They're sold out everywhere.
When things sell out, that is when the price jumps.
LL.com, NN.com, LLL.com, NNN.com, LLLL.com, and NNNN.com all sold out and the prices quickly jumped up because the people who owned them called the shots. If your NNNN.com isn't available to register, you cannot settle for another one by registration, you HAVE to buy it from someone else. That someone else wants to make a profit (or else why would they have bought it if they're selling it?). $15-$20 is not a bad price to expect for low end NNNNN.coms within a few months of them selling out.
Give it a year, you can expect mid xx to low xxx for them.
There are only 100,000 combinations. Say you buy 100 (small investment for some domainers) for $1,000 ($10 a registration). You now have the right to .1% of the entire market. To hit that market penetration with LLLL.coms you'd have to buy over 450 domains (26^4 /1,000 for you math geeks).