I’ve gone the route of the WinCE-based WebDT366 LX800
http://www.webdt.org .
It is a weather-resistant, touch screen, flash memory driven, beast. I did not say it was a sprinter, but like my

, it does what it is supposed to do well. The OS has been replaced with a slimmed down version of WinXP and I am using OpenCPN
http://www.opencpn.org for my chartplotting. I toyed with a USB mouse GPS, tried to run NMEA from my replacement Eagle 350s sounder/map, and ended with a Bluetooth GPS attached to the mounting frame of the tablet.
The cost breakdown is as follows:
WebDT366 $100 (Ebay)
G-sat GPS $35 (Ebay)
Ram mount $50 (WM)
OpenCPN free
Charts free
Satisfaction of having a 8.5”x6” macdaddy chartplotter under $200... priceless.