Companies price their server software this way for the same reason that airlines charge last minute (i.e. business) travelers more than leisure travelers: price discrimination. In other words, charge more to those who are willing to pay more, less to those who are willing to pay less. Sofware firms are in it for the money, after all.

I use an iBook with RDC to my WinXP desktop. I get a good-sized keyboard, very good battery life, and acceptable WiFi performance. Granted, video plays poorly via RDC, but cut-and-paste works betweent RDC (I use RDC in a window) and Mac OS X, so if I have to pull up a video URL, I don't have too many problems.

The iBook is very reasonably priced for this purpose; at $1100-$1200 to set up, it makes working wirelessly on a desktop a lot more fun (and then you can start thinking about getting rid of your desktop monitor and keyboard, and sticking the CPU in a more unobtrusive place . . . and opening port 3389 on your firewall at home, so you can use your home fixed IP to access the machine via RDC . . . )