Evocation [Force]
Level: Sorcerer 4, Wizard 4
Components: V, S, M
Casting Time: 1 standard action
Range: Close (25 ft. + 5 ft./2 levels)
Effect: 3-ft.-diameter disk of force
Duration: 1 hour/level
Saving Throw: None
Spell Resistance: No
You create a slightly concave, circular plane of force that follows you about and carries loads for you. The disk is 3 feet in diameter and 1 inch deep at its center. It can hold 100 pounds of weight per caster level. (If used to transport a liquid, its capacity is 2 gallons.) However it is moved it remains level with respect to the direction of gravity so its contents do not spill. Unless otherwise directed, the disk moves to remain within 15 feet of you. Unlike floating disk, a greater floating disk does not have to remain 3 feet off the ground. It floats along within spell range and will accompany you at a rate of no more than your normal speed each round. The disk winks out of existence when the spell duration expires. The disk also winks out if you move beyond spell range (by moving too fast or by such means as a teleport spell). When the disk winks out, whatever it was supporting falls to the surface beneath it.
You can concentrate (as a standard action) on the disk to make it move with a fly speed of 20 feet (perfect). This allows you to sit on the disk and command it to carry you about.
Material Component: A drop of mercury.
Source: Spell Compendium, page 95. The spell description needed some rewriting to remove contradicitions and ambiguities.