you really don't want that. imagine a confusion you'd have all the time when using software. say a year from now, you launch your older wallet software, and sen

you really don't want that. imagine a confusion you'd have all the time when using software. say a year from now, you launch your older wallet software, and send 1 (old btc) instead of 1 (new btc) to someone. You'd need to double check every single place you'd ever spend bitcoins on to make sure that it's new bitcoins and not old bitcoins. Similarily with software - everyone in the source code it'd say "bitcoin" programmers would need to check whether it's new or old. The amount of confusion, and engineering work would be staggering. It's far better to have a new term alltogether. People have been proposing "millis" or "millibits".