Today the visa expediter (VisaHQ.com) returned my passport via FedEX. As seen below, there was no visa attached and no explanation of why this visa was not issued (I later was told that they were still waiting for approval from the Sudan foreign ministry).
At least I have my passport back. This lets me fly to Cairo where my next step will be to apply for a visa at the Sudan Embassy in Cairo. Apparently, the embassy in Cairo is in new quarters, so will have to find the new location.
Rather frustrating to have sent away my passport nine weeks ago and then not yet have the visa.