Although from my brief discussions with Arve it sounded like the semantics of the android alarm timer interface is a little particular (especially with regards to wakelocks), so I doubt there will be an alternate implementation that will provide an exact 1:1 mapping.
That said, the rework of the RTC layer as well as the implementation of CLOCK_BOOTTIME (tglx just pulled it into -tip) will hopefully greatly simplify the android alarm timer code. So there may be a future for both the posix alarm timers and some form of the /dev/alarm device to co-exist, sharing a good bit of code.
Even so, while I think the posix interface for alarm timers provides a fairly nice and consistent interface that application developers are used to using, I'd greatly appreciate feedback and suggestions for alternative interfaces. Maybe we need something like clock_select()?