Well, they'd be more mobile. The general effect can be achieved by increasing movement and using split movement feats or effects, by variations on haste, and by effects that insert extra actions, ranging from something based on Expeditious Retreat up through an item based on Time Stop.
The Practical Enchanter has a section on enhancing movement and actions, either as items or as talents and Eclipse has a variety of ability chains (Reflex Action, Split Movement, Celerity, Etc) which can accomplish the same thing.
A simple extra Move action sounds like a L2 spell: it's not as effective as Haste. So: Boots of the Hummingbird perhaps. Or Cloak of Mobility. In Eclipse it would be easiest to create it as a minor item granting Reflex Action specialized in Movement, and Corrupted (only usable every so-many rounds to keep it from being grossly abused) thus allowing a character to move-full attack-move every so often.