Actually, Rasberry Pi runs on an ARM microprocessor and OpenBSD is a whole lot more ARM-friendly than most Linux flavors are. It should not be hard at all to get it running yourself.
Any mortal who wants to run BSD is most likely also capable of installing BSD. (For that matter I'm sure the majority of people who have just heard of BSD are capable of installing it.) Furthermore it's no more difficult getting up and running than on a desktop since the Arm is supported by the kernel; you just load everything on the SD card and the pre-installed uboot (or whatever they have on there) will boot off of it.
It's not that simple, an ARM board is not a PC, you don't have a BIOS for instance. Basically you have to write some glue to tell the kernel what and where are the devices and how to access them.
Not to mention that while OpenBSD supports the ARM architecture it might not have drivers for all the IPs integrated in the SoC.
So basically, it won't be plug'n'play like installing a new OS on your new x86 computer, altho the amount of work required to get it to work might not be completely overwhelming if you know what you have to do (especially since the linux source code is available).
