Why look for new cross-sections ? An all-new design would take us well into the '20-ies and we'd have to foot the bill for 13 billion USD in non-recurrent R&D costs... when we have ready available for "immediate" (maximum three years from Project Go-Ahead to EIS in commercial service) application the HQR (1+3+1) or HP3 (1+2+2) Twin Aisle variants for both A320 series and 737 series : I gather your Flight Attendants would welcome these new toys ?/FT

Enter the twin-aisle narrowbody - Runway Girl