2 years back I stayed at a very secure house owned by Marsland Aviation (they accommodate their pilots their) they'll rent the entire 8 sleeper house to you for about US$350 per day. It has electricity, beds, fridge, satellite TV and aircon.
If you can't afford the price why not call them anyway and see if you can share the house, or if they can find somewhere else for you at a cheaper rate.
Speak to the Manager of Marsland:
Sadig (Cel): +249 (0)91 234 0789
If this doesn't work call Marco of 5m Car hire in Khartoum he is well contacted and like most expat/Sudanese very friendly and helpful (if you hire your Khartoum car from him) will probably fall over himself to help you whether it be accommodation in Nyala, El Geneina or al Fashir.
Marco Tarag (cell) +249 (0)91 230 1905
