Well these tablets are in general too large for my tastes. Yeah I'm no fan of the SL4. Too big to hold like a paperback.
The exception is the Teklogix NetPad, which has an HPC-like screen
(slimmer 640x240 at 8 inches
). It is still a popular item on eBay. However that resolution would be bad in portrait, just like a QVGA PPC.
I'm still hoping to find a Smartbook G168A one day. That would be perfect!