Twenty posts and still going.
The silly thing (in my opinion) is that only a pedant is going to misunderstand anyway. If we really think that there is some horrible risk of misunderstanding, we could , depending on what we mean exactly, say something like:
We sell four iPods a day.
We get four enquiries a day about iPods.
One nutter comes into our store four times a day to ask stupid questions about iPods.