Re: There is virtually no affordable hardware out there
"take the specifications made for PPC and just apply them to ARM. After all there were full specifications for PPC-PCs"
Assuming you mean the Advanced RISC Computing/Advanced Computing Environment  folks and the associated specs, it included not only PPC but also Alpha (from DEC and others), MIPS, and even some x86 (from SGI):
But the primary target OS seemed to be Windows NT. In addition, Linux was supported via Milo, which Dave Rusling may well remember , so when NT reverted to x86-only, ACE (and ARC) kind of disappeared too, in due course.
An ARM variant might be an interesting idea (or might have been, at one time).