> >> Are the mmeye and evbsh3 different enough to warrent their own top-level
> >> sys/arch directories?

Yes.
mmeye and evbsh3 are MACHINE dependent part, and sh3 only contains
machine independent (but MACHINE_ARCH dependent) part.

> Yah, it's pretty disgusting. 'arch/sh3/sh3' contains device drivers,

It is not problem, because I think that all these drivers are for
sh3 on-chip devices. (aren't these?)

> and seems not consistent to have 3 different 'arch/XXX/' directories.
> If 'arch/sh3/' services backending common library (as 'm68k' or
> 'mips') for particular ports, whole things should be done differently. 

I think proposed directory hierarchy already conforms what you said. :-)
--
soda