Maybe you hate being printing pdfs, and webs to take a look them at night, or reading in your laptot, and seeing that a tablet pc costs more than $2500, today I have seen an interesting project: techcrunchit webtablet I have add some specifications:
harddisk OCZ Rally2 8GB USB or A-Data 4GB Compact Flash
motherboard MX800LX2D http://www.bcmcom.com/bcm_product_mx800lx2.htm
memory A-DATA 1GB 184-Pin
the motherboard is the latest fanless I have find on the web, and it can be connected directly to 12V.
I think two possibilities,
1.- use a USB as a hardisk (I do not know if the bios can boot from USB)
with a wireless module on the CF module.
2.- use a USB wifi module with a CF hardisk.
Both kind of wifi modules has antenna conector, so is possible to extend the wifi range.
I think the biggest issue in this project is a cheap 800x600 or 1024x768 SVGA panel up to 100$ with A4 size, I have found this kits:
59$ the 12.1 model
with touch for 123$
SO IS POSSIBLE, if you know interesting info reply in the forum