The problem with most netbooks is the low resolution 1024x600. If you're reading short e-mail/web pages and viewing youtube video, then this is adequate. I owned a MSI Wind, but the poorly built cramped keyboard causes strain after long use. If you're a touch typist, it will cause you to mistype when you switch back to a full sized keyboard due to muscle memory. In addition, the touchpad on the MSI Wind is unusable. It's best to use an external mouse. It made for a horrible user experience that I ended up replacing it. This is basically what the Apple folks concluded when asked about netbooks.
I replaced the MSI Wind with a HP Mini 2140 with HD (1366x768). This has an almost full sized keyboard which is quite comfortable to use. The HD display is absolutely gorgeous and has enough resolution to view large documents. Programmers will love the display as one can see more lines of code. The only problem is the higher resolution results in the pixel being smaller. People that have bad eyes are going to have a hard time with the smaller 10" display and is going to cause eye strain. The trackpad button placement is also a bit awkward and the touchpad itself could use more vertical space. These are minor problems that I could live with though. If the display were 11", then I think we have the sweet spot. If they built this, I imagine more people would replace their existing laptops with netbooks. Of course, that would cut in on the manufacturer's laptop sales. I don't think that will happen.