it might be me but it sounded like you listed the same option twice!

what i did with my alarm clock was i split the shell up, then i arranged it how i thought it would go when in robot mode and put in blocks for the actual robot limbs

originally what i was going to do was set up set driven keys on parent constraints and modify the pieces after it was rigged

but i found by doing that i couldn't do things like mirroring or combining and all such things that make modelling easy because then i'd lose the set driven keys and constraints

so i duplicated the entire robot without the shell, moved it over and just started detailing on that and i would bring it back to the original to see if it was still the correct size. (but then the shell can always change size to adjust for larger limbs..)

...but i dont think that answers your question, eh...?