First, I want to thank you for your great efforts. I haven't tried Arch for more than half a year on my N900, and I was amazed how smooth the whole instalation worked out. Even more, I couldn't believe my eyes when I saw that you even had adapted the whole thing to systemd already.
This is just a dream come true.

That is quite easy indeed. All you need is to setup acpid (and acpi). Both the power button and the screen lock trigger acpi events.

Any chance that you'll release the PKBUILDs of your packages (especially for linux-n900)? For example, cryptsetup isn't working properly, as it can't load/use the dm_mod kernel module, or I'd like to try out omapfb vs omapdrm. Usually, I'd just have recompiled the kernel (or the needed modules), but that's quite a bunch of work without the PKGBUILD scripts and patches you used. :/

regards
Pascal