OCZ have just announced the release of a Do-It-Yourself notebook enabling gamers and enthusaists to customize the laptop how they like. The barebones notebook retails at around £350.
There are a few problems with this idea however. While you can choose the HDD, memory and CPU, the GPU used is an 8600M. While this is adequate for some basic games, good luck playing anything contemporary at medium to high quality.
Also, the cost of the whole package, after adding all the extra bits you need for the system to actually work, the cost is likely to reach over $1000. This makes the whole system less cost efficient than many prebuilt systems making the DIY idea seem more like a gimmick than anything.