Hey...
If the time has run out, that's fine...
If you are still interested, here is what I will need to fall within your constraints...

You provide me with excellent Ariel Photographs and a mating digital terrain (DEM) and I can "Git-er-done" in short order... The process is very time consuming and tedious... but using Ariel photos rather than Satalite imagrey will provide you with extremely high resolution terrain.... I break the terrain into many pieces with 4 files per piece for LOD to maintain high FPS... Then you or I can use Digital images of the actual structures and locate them exactly where they belong per the Ariel photos...
Regards,
Paul