HP seems to make a lot of weird design decisions on some of their consumer hardware. :-/
I'm running dual 21" Samsung (1900x1200) monitors off my Dell E6400 notebook (with a docking station). They're TN but good enough for the work I do. The graphics chip in the E6400 can overheat doing this, or at least it did until I stuck a CoolerMaster laptop cooler under it. Later machines may not have this issue.
I'd strongly recommend a not dismissing a decent 15" laptop with a crappy screen, a docking station, then you can get the monitors you want. Speed, quiet, low power consumption, the opportunity for portability. The docking station makes it easier to add external storage, too.
Have fun.
Cheers,
Scott.
(Who got one of these a few weeks ago, but I haven't tried to use it as a monitor -
http://www.amazon.co...ps&condition=used It was used but "like new" so the price was great and it still had the original packing (though in a different box). 42" might be a bit big as a computer monitor though. ;-) The picture is great in HD, OK in SD.)