The bit driver... and every OTHER tool on it, ARE all replaceable.
If you want smaller, maybe the Pocket Power Plier, get the socket driver for it, remove the (worthless) can opener, and maybe swap the awl to the other side (losing one short tool there), or just ditching the phillips.
For that 'no space wasted' feeling, I think Leatherman might be it for you. Maybe get a Rebar with the bit adapter. Or a Charge TTi with bit driver extender (to use standard hex bits).