For the last eight years or so I've wanted this sort of device (with of course the design needs going up over time).
Portable Server:
Runs Linux
Does not use batteries but instead uses wall power.
No monitor, just ethernet (use a boot loader via a web browser)
Does have USB (need this to load the OS via CDROM, but this could be skipped...)
Is under five pounds.
Solid state disk.
Suspend to disk.
Five pounds or less.
Dimensions of a book, but can be a bit thicker (needs to fit into my backpack)
64bit, 4 or more cores
4 or more gigs of RAM
Switching power supply (aka can use anywhere in the world)
Wireless would be a nice "have". I'll string cables though if need be...
I feel like technology is getting closer to my needs...
I trust no development that is done on 32bit machines with single processors, and if your tests don't push your environment past 2gigs I am skeptical as well.
(...and yes this is because I work on server related stuff like MySQL, if you are working on embedded I wouldn't trust the work unless you tested it on machines with tiny amounts of memory).