Theoretically you would be constantly between 20%-65% increased run speed at all times (although about 35% would be more realistic)

12 Nightblade for Stealth, +15% damage to attacks, Hellfire Blades enchantment

21 Bard for +20% run speed in combat, Motif of Restoration, +10 STR/DEX, +10% health.

33 Marksman for all of its goodies including the upgrade so that Swift Shot increases run speed by 5% (can stack up to 5 times) and +4% run speed when attacked by enemy (can stack up to 5 times).