[judgardner]

Server lifts are pretty common kit in most colocations.

http://www.material-lifts.com/client_images/catalog19960/pag...

[peterwwillis]

Barring those (and the space to fit it between the racks), you could attach tracks on the ceiling and use a moving chain & pulley to move them around with just one person. Granted, with double racks you'd still need a ladder to attach the chain.