Sony NEX-5 with 1440-7200mm Zoom Lens
GK emptied out his photo bag and came up with this monster.
NEX-5 with flash, Sony LA-EA1 adapter, MD->MA adapter, Cosina 2x, Vivitar 2x and Tamron 2x teleconverters, Minolta MD extension ring set (28mm, 21mm, and 14mm), Vivitar 120-600 f5.6-8 MD mount lens, 82mm lens hood.
So if our math is correct, the effective focal length is 120-600mm * 1.5x [sensor] * (2x)^3 [teleconverters] = 1440 to 7200mm.
This is assuming that the MD>MA adapter is 1:1.