Try contacting "Deluxe Travel"
contact information http://www.egyptholidaysdirectory.com/listing/deluxe-travel-egypt-travel-agency-tour-operator-travel-agent.html about 8 years ago
It depends what you mean by 'Nile cruise'. I think most of these are simply ghastly! However, we found this little private operator who takes you out on his Felucca down at Aswan: http://www.aswan-individual.com/
They are very helpful and have a relationship with a Nubian called Mustafa who has thew most delightful boat (this is my son on his boat: http://journals.worldnomads.com/simon_monk/gallery/20459/596228.aspx
Highly recommended. His mobile is 002 - 010 - 4605323 about 8 years ago