Just did some digging, and found out that the company AEI launched a 737-800 conversion program on March 31, 2013. The program included options for both SF (full freighter) and C (combi pax/cargo) upgrades for the aircraft. I believe only the SF ever attracted orders (such as West Atlantic) but it'd be nice to see the C variant in the game as a conversion option from that date. It'd be perfect for routes such as SEA-ANC, where a -700 just doesn't have the pax capacity. The full freighter would be helpful as well.