I think Priffe posted some information about this recently?
I've been following the Ivory Coast situation for a while now and still have found no evidence that a visa could be obtained on the border.
People have reported that the Visa D'Entente is still available from Ougadougou, Burkina Faso, which would be the cheapest way of getting a visa for Ivory Coast.
But will the authorities accept the Visa D'Entente at that border? I don't know the answer to that. I don't see why not, but some people in recent years have been refused entry to Ivory Coast with the Visa D'Entente. This was during Gbagbo's rule though.
Whatever happens I would sure appreciate you posting where you get the visa from and how much it costs.