Hi Martin,
Although not a direct reply to your post (or even my original one) - I thought I would post again here just in case it will come in handy to someone.
Since my original post, I've investigated several options - including buying and testing two NSLU2 devices. It was all great and good - as I was aiming for very low power consumption and a compact size - but the hassle of it was too much. I wanted a device which will do everything in one - and would be relatively easy(er) to configure.
I ended up actually using one of my 4 year old HP/Compaq V2120 (I think) laptops. This laptop has a Broadcom chipset which supports hostap/master mode with Linux kernel wifi drivers.
After about 2 weeks of research and trial and error (and few more months of tweaking and tuning) - I ended up with a single machine which performs the following for me:
1. Wireless access point.
2. OpenVPN router
3. Asterisk (VoIP) server.
4. Small scale email server (exim + dovecot) including emailing me the voicemail messages as attachments.
5. WiFi sound system - using PulseAudio over network - and connected to two large speakers - thus it plays over wifi sound from my regular/work laptop - including watching films.
6. Firewall and router towards my Internet connection.
I have used a Sangoma U100 USB FXO card to plug it into the phone line as well - so it picks up my phone line and diverts it to my mobile (through VoIP provider) and/or takes messages and emails them to me.
I know, it is more expensive (although I already had this laptop, so not to me in the context), it is a bit more power hungry, and far faster then it needed to be. On the plus side, however:
1. It is a x86 machine, with an integrated screen - a lot easier and faster to setup, troubleshoot and maintain.
2. It is a x86 machine - thus I could use Slackware (or insert here your favourite distro) - which I was already familiar and (more) proficient with.
3. It is an x86 machine - so availability of software for Linux is better then any other architecture.
4. Although not as power efficient as the ARM based machine - with the lid closed (and screen off this way) it measures about 18W-20W. With the router or NSLU2 I would have had to add another external hard-drive for storage - which would have added another 5W anyway - in total 10W - plus the extra connections.
5. It is more repairable then the NSLU2 - I can replace and expand the external hard-disk at least.
I was (and still am to a certain extent) a big fan of the embedded platforms like the routers and NSLU's - but for the sheer speed and convenience of setup - and the fact that I have everything in one (no external hard-drive or usb memory stick, no external sound card) - well - except for the Sangoma U100 (which I would have never been able to find drivers for ARM anyway) - an x86 laptop was just the ticket for me.
It has been running now non-stop since February (almost 7 months) and quietly doing everything for me. Whenever it will break - I will replace it with one of the current netbooks - which (with the lid closed) should bring the power consumption below 10W - well within the range of an NSLU2 or router plus external hard-disk - but with far more power and convenience. Also, with a bit of luck - it might be a passively cooled netbook - with no fan to break over extended use.
The key to the whole setup is finding a machine with one of the Broadcom chips which can definitely work in host/master mode with hostap software. The kernel wifi project/pages should have further information - but it took a lot of figuring when I last looked at it to make sure you get the right chipset. At the time - the hostap software configuration took a lot of guessing - but hopefully it will be more user friendly as time passes by. There might be some other wifi chipsets which work in hostap mode - at the time I could only figure out the Broadcom one.
Also the laptop as a router/wifi access point would allow me to plug in directly a USB ADSL modem - if I ever move back to ADSL internet - which again would avoid having another device with another power supply involved - and would provide more control over the Internet connection directly from my server/router/multi-function-time-machine 
.
Well - this is at least what worked for me.
Good luck,
Sebastian
P.S. - Oh - one more thing. For the purpose of turning a high-res webcam into a wifi cctv cam - I've settled in my mind on an Asus EEE 700 series - or similar. It would have no problems working in wifi client mode, regardless of wifi chipset, it would offer 2 (or 3?) usb ports to be used for the web cam, plenty of onboard storage compared to a router (even the smallest EEE, at 4GB), and at the moment they are as low as £129 in UK. Close enough to a high end Asus router. But it has a screen, and it is x86, and it even has a sound card - if ever needed. And I certainly know where to get software and drivers for it .
(Last edited by xj25vm on 18 Sep 2009, 20:49)
