Visa is for entry. If she doesn't need to enter, then she doesn't need a visa. If she wants to change status inside the US for her current stay, she can file I-539 for Change of Status. By the way, B1 is for business visitors; B2 is for personal visitors. If you are maintaining L1 status, there is no reason why she wouldn't continue to be in L2 status.
If she wishes to enter in B1 status for her next entry, she can apply for a B1 visa at a US consulate abroad, after she leaves the US.