Sure. Two examples of items that can accomplish this would be the easy travel armor enhancement from Magic Item Compendium (+1500 gp, allows you to treat a medium load as a light load) or the tooth of Savnok from Tome of Magic (2000 gp, allows you to move at normal speed when wearing medium or heavy armor or when carrying a medium or heavy load, but causes you to suffer Savnok's sign and influence).