> Oh yes - please do.

Ok, I did.

> It's not just pickle size - going through str() makes (un)pickling quadratic time in both directions if components are large.

Yeah, I noticed speedup too, but size was much more important for may application.

BTW, the same issue affects some other stdlib modules, ex. in the Decimal() it will be more efficient to use the tuple (sign, digit_tuple, exponent) instead of dumping strings.  Maybe more, simple fgrep suggests me also the ipaddress module, but I think here it's ok;-)