True - but at the same time, about half¹ of it is mipsel, i.e. in little-endian mode :). It's also in decline, AFAICS there is very little new silicon development.
Many routers use the MIPS ISA and they can be rooted to get shell access. That's what I did with an old Netgear router, which was like a very low spec SBC. If you have a PS2 lying around, you could try that.
¹ on the OpenWRT table of hardware