almost ...
the isp is not permanent (to save costs - I plan on having several 'targets')
the target is 'hidden', but I would have a connector that can be reached - and would allow to reprogram and debug
the isp would be hooked up to this connector to allow reprogramming fuses/sketch - maybe even serial communication to allow debugging
so basicaly - a icsp header with added tx/rx - would cover everything I think
so far not much joy on my breadboard experiment - but i'm pretty sure it can be done
I must be overlooking something obvious and simple - right now I'm having trouble using my Uno as isp too
Ah - it is very late and sleep deprivation doesnt help with this sort of thing 
Thanks for your insights, they really help a lot!
quick update:
using usb and the uno as isp - i can program a target on the breadboard
but using rs232 and a 328p i keep getting an error 'avrdude: stk500_recv(): programmer is not responding'
tomorrow I'm going to double check that serial communication is working, and I'm going to try serial communication with the uno as isp
Any other trouble shooting tips are welcome
btw - using the uno as isp is problematic, to say the least - i'm not even going into that as I don't think it is related, or relevant to this experiment