Here are the last four sections of my document on parting together a cheap laptop. Hopefully someone will see that they don't have to live without a laptop if they have some time and a little bit of money. For the record, my most recent machine cost about $30 out of pocket, although I had some of the parts already, have a junk pile at work to pull some of the other pieces (plastic bezels, that kind of thing), and have friends that love me - you know who you are =).
Part III: Beg, borrow, but don't steal!
Let's review: we know what device we are building and what we need to get the system to a minimum usable level. How do we best obtain the missing parts?
Obviously, the first thought is eBay. However, let us step back a notch. Do you have friends in IT? Friends who run through laptops quickly (read: sales, marketing, executives)? Start asking around and find out if anyone has extra parts you can bum off of them. Perhaps you will even score a complete, but dead, machine. A whole dead machine will be one of your best sources of parts, especially the little stuff (screws, spacers, shielding, insulation). Of course, finding a mostly complete machine may lead you to change your plans a bit.
Check to see what parts you have left to get. Now is the time to check eBay, craigslist, and so forth. Get a feel for how much the parts are going for. Don't forget to search for parts for compatible machines as well – you may find the part is cheaper when listed under a different model. You may find that your best bang for the buck is dead machines. This is pretty much your last chance to get out of this without a financial impact. If the required parts are too expensive, go back to finding cheaper alternatives, change your requirements, or give up.
Part IV: Assembling the system.
If possible, begin assembling your system as parts arrive. You want to test critical components such as the motherboard as soon as possible to judge the financial impact if they fail Repeat the examination process from Part II with each of the components you are planning on using. Parting together a system leaves some room for creativity. If you leave out a component (floppy drive, optical drive, internal speakers, and so forth), you can replace it with something else (USB hub, bluetooth controller, USB wireless, etc). At the end of this document there are a few links; the one to hackaday leads to a good article on being creative with the old hardware.
Break out the maintenance manual you downloaded earlier and start assembling. Be careful, and follow the directions whenever possible. Having to completely disassemble a mostly assembled laptop can be a little deflating. When you're done, you should have a more-or-less complete looking laptop.
Part V. Final Steps
All that is left to do is install your operating system and test the laptop. I usually recommend installing a recent version of Windows for testing purposes, and once assured that the system is functional, move to Linux or whatever version of Windows you have a license for and begin the fun of getting drivers and everything else working. Personally, I dual-boot Win2k and SUSE 10 on my system. Many people have good luck with Ubuntu Linux; I'm just not one of them.
Part VI: Links
http://laptops.hackaday.com/entry/1234000800056067/ - Project parting together two Thinkpad i-series laptops. Good tips for customizing any laptop.
http://www.makezine.com/blog/archive/2005/12/adding_internal_bluetooth_on_a.html – Add internal Bluetooth to a machine that didn't come with it originally.
http://www.macmod.com/content/view/404/101/ - When looks don't matter (or they do, depending on your taste)...
http://www.linux-laptop.net/ - Linux on Laptops, a good, specific guide to getting Linux running on different laptop models.
http://www20.tomshardware.com/howto/20050504/index.html – Tom's Hardware Guide article on building your own laptop out of barebone parts. This is the type of thing I alluded to at the end of Part I.
Well, that's it for this one. I may revise and repost it later as I think of ways to clarify my thoughts, but I think it should give anyone looking to go this route a few things to think about.