Yes
Your question is simple and thus it deserves a simple answer.
Are RaspberryPi's ever on topic for ServerFault?
Simply, RaspberryPi is a hardware platform. There are all kind of business applications of RaspberryPi. I've used it in business to establish a VPN bridge to Amazon. I've also used it to do all kinds of things.
Serverfault is a pretty bad idea, but the second you enter the world of business-applications it becomes a business platform and it is therefore on topic. Any attempt to exclude it is more because ServerFault wants to cut an a niche that is more exclusive than the inclusiveness found in a $35 platform.
Is it a totally bad idea that merely having a low-cost platform in a different place can make the question on topic? Yes -- it's a horrible idea. But, ServerFault's admin team doesn't seem to have the intellectual prowess to tackle that.
Let's keep in mind we're talking about a site that is plagued with questions about petty user-software like vim. I'd contend if VIM was ontopic merely because it was on a server than the hardware platform running my ltsp should be on topic.
