Wifi is used by millions of people every day to connect wirelessly to the
Internet. True, far fewer people use it to connect to, e.g., printers,
cameras, etc.
It's a fair bet that if you can't buy an Ethernet version of some
peripheral, you won't find a WiFi version -- hence, no WiFi mouse. On the
other hand, Bluetooth mice are quite common.
But the real reason I wrote this is to point out this web site:
http://cs.gmu.edu/~sean/stuff/n800/ -- It gives a very good perspective, I
think, on the difference between development "from scratch" (the Apple
Newton) and the more contemporary "amalgamation" approach (the Nokia N800,
which uses Linux albeit with plenty of custom additions by Nokia). As you
might expect, the Newton ends up having a much "cleaner" user interface,
even though the software available for it and the raw hardware feature set
is nothing compared to the N800. But of course it's a different world now
than it was back in 1995 when the Newton came out -- back then it still
seemed like most people were truly passionate about design, and what I think
of as innovative features of the Newton -- stuff like using the edges of the
screen for multiples "clipboards" (see the web page) -- these days is
ignored by Joe Sixpack developer who has a bullet point item of, "Must
support cut/copy/paste" and implements the most boring and limited
Windows-like single-entry clipboard model possible. (Although if one is
looking for passionate designers, Linux or OS X is probably a much beteter
place to look than Windows...)
Reading that page also made me think of your request for a portable
schematic entry device: Portling something like KICAD
(
http://iut-tice.ujf-grenoble.fr/kicad/) would probably be about the fastest
route to getting something usable. The main limitation appears to be that,
while the N800 has built-in support for a Bluetooth keyboard, it's missing
support for Bluetooth mice (something I'm sure an enterprising Linux hacker
could readily fix).