Some routes local to me that have either been tried or certainly could have potential are;
Birmingham-Mumbai now TATA have taken over Land Rover and Jaguar.
Birmingham-Chicago maybe a long shot due to Oil and state of US Airlines.
Birmingham-Any Berlin Airport should be considered by BE/LH/WW/FR
Birmingham-Stockholm Arlanda (FR are to commence NYO this month) Birmingham-Athens has been operated before and was well supported.
Birmingham-Istanbul was being planned by TK but all has gone quiet.
Birmingham-Dhaka certainly there would be large local community support.
Birmingham-Middle East destination Ethiad have mentioned BHX.
Birmingham-Orlando/Florida BHX has only 1 SFB flight per week.
East Midlands-Pakistan
East Midlands-India certainly the communities could support BHX and EMA with sub continent services.
Just my thoughts
Daza