Looking for a good driver development training example

Hi,

I'm trying to learn how to develop Linux device drivers and I thought that
"embedded" could be an interesting choice, knowing that I have an IPAQ 4150
available at home.

"Unfortunately", I guess that all possible drivers are available already (I
can't check that at the moment, handhelds.org is down). I have no special
hardware, just a plain standard IPAQ 4150 (and two PCs, Intel and AMD
based). The perfect case for me would be if I could adapt or port an
existing driver.

I also thought of maybe buying some kind of very cheap and very simple robot
that I would connect to my serial port and try to control it from my PC.

My final aim is to find a job in that kind of area (Linux kernel
development) in 6 months or so.

In the mean time, I have plenty of time and enthusiasm. I'm just lacking the
inspiration. My background is in software development although a bit rusty.

I believe in "learning by doing" and am looking for an example as close as
possible to real life. Even a real life project would be welcome although I
wouldn't be able to give any garantees in terms of completion time.

I welcome any idea.

Cheers,

Alain