I had wanted to add a furler for our staysail but the sailmaker convinced me not to do it.
His reasons: Weight and windage aloft, staysail (uv cover) would get chafed by sheets for the jib (and possibly tacking without furling the jib), and no easy way to set a storm jib.
So, what we ended up with was a hanked on, self tacking, reef-able staysail (already had it) in a ready bag (always hanked on) and a storm jib.
Time will tell if it was the right decision or not.
Cheers,
JM.