ARM Development for the Office: Unboxing an Ampere EMag Workstation
anandtech.com
anandtech.com
Better yet, there are ARM Chromebooks, so it's not like Google considers it experimental support or something.
Open source in general seems to mostly handle different platforms nicely; other than the odd program that assumes things about word size or endianness or whatever, it's usually just a recompile away. Heck, NetBSD and OpenBSD still happily support sparc :)
It seems like what people really want is a many-core ARM SoC in a laptop. Turn most of the cores off when doing simple stuff on battery power, then turn them on for bursty parallelizable tasks like compiling code.
I like the Marvell MACCHIATObin, A72 @ 2GHz runs Firefox well enough.