In my endless pursuit to find information on new large aircraft and to collect those priceless-if-useless bits of aviation psuedo-history, I have come across this outdated (1998) report by the FAA on how airports will cope with "new large aircraft". http://www.tc.faa.gov/its/worldpac/techrpt/ar97-26.pdf
The document includes issues involving the following aircraft, and ends with elementary side and top views of all of them as well as highly detailed information:
Boeing 777-200B (we call it the -200IGS)
Boeing 777-300 (wasn't around back then!)
Boeing HSCT (High Speed Civil Transport)
Boeing 747-600X (That's me!!!)
MD-XX (Stretched MD-11)
MD-XXLR (Long-Range Stretched MD-11)
MD-HSCT (Similar to Boeing HSCT)
We call the A3XX the A380 nowadays, but what's interesting is that you can't find schematics for the stretched model of the A380 (A380-900). This document provides a curious look at what the A3XX-200 (A380-900) might [have] look[ed] like.
One interesting point is that the 747-500X and -600X were shown as having four-wheel nose landing gears. Curious. The HSCTs also had EIGHT wheel main bogies.