Let Motion know what you want out of the LS800 successor.
Me personally, I'm happy with the specs as far as speed and hard drive size. What I want in this device is a couple of small, low CFM fans that will slowly circulate air through the device so it doesn't overheat. When Tablets first came out I purchased the M1300 because it had no fan, but with this small device that heats up so quickly we need more reliability. Mobility without reliability is useless. I can't use it as a unified device and leave my notepad at home if I'm unsure as to whether the device will be able to work all the time.
I would also like the option of up to 2 GB of RAM, ram that is user upgradable most particularly.
A big factor would be a better standard battery, being the same size as the current battery, or two standard battery bays: one on either side of the screen so the screen is more centered. Probably won't happen because of the location of the ports and the design of the mainboard.
A nice feature would be optional pen upgrades, pens that still fit in the garage but include upgrades such as erasers, cushioned grips, nicer material, or even a pen with a rotating cap that includes an ink tip that can pop down to replace the stylus tip. That would be a big selling feature for me. I'd spend money on the best pen option.
If a ULV dual core cpu were available I would be fine with that being included, and a good GPU would be fine by me, but these things probably won't make me want the device more or be more willing to spend the money on them.
The things I want from a device are small size (like the LS800), a good screen, good battery life, and high reliability.