I THOUGHT OF THIS TOO!
Something like a Galaxy or such, that got no room for passengers (only gunners) and a highpower-magnet under its bottom.
The magnet can pull to '10 weight bars' so it could transport:
- 1 large tank ( 8 bars )
- 1 Sunderer ^^ ( 6 bars )
- 2 light tanks ( each weights 5 bars )
- 10 Quads ( 1 bar each Quad )