I don't know what you mean by a Shadow Stalker.
If you can use PF feats, though, UC has a line of feats that might be useful. (Itsucks for monks, despite what the "Special" line might lead you to believe, don't try it with a monk)
[sblock]
Dimensional Agility
Teleportation does not faze you.
Prerequisites: Ability to use the abundant step class feature or cast dimension door.
Benefit: After using abundant step or casting dimension door, you can take any actions you still have remaining on your turn. You also gain a +4 bonus on Concentration checks when casting teleportation spells.
Dimensional Assault
You have been trained to use magical movement as part of your combat tactics.
Prerequisites: Ability to use the abundant step class feature or cast dimension door, Dimensional Agility.
Benefit: As a full-round action, you use abundant step or cast dimension door as a special charge. Doing so allows you to teleport up to double your current speed (up to the maximum distance allowed by the spell or ability) and to make the attack normally allowed on a charge.
Dimensional Dervish
You teleport with a mere thought, savaging your opponents as you flash in and out of reality.
Prerequisites: Ability to use the abundant step class feature or cast dimension door, Dimensional Agility, Dimensional Assault, base attack bonus +6.
Benefit: You can take a full-attack action, activating abundant step or casting dimension door as a swift action. If your do, you can teleport up to twice your speed (up to the maximum distance allowed by the spell or ability), dividing this teleportation into increments you use before your first attack, between each attack, and after your last attack. You must teleport at least 5 feet each time you teleport.
Special: A monk can use additional points from his ki pool to increase his speed before determining the total speed for this teleportation.[/sblock]
You might also want to look at a Swift Hunter build (Scout/Ranger).
Back to Swordsage, the Desert Tempest, Ring of Fire, and Tornado Throw maneuvers all directly benefit from high speed to do more damage and/or hit more enemies.
Right now, I am playing in a high level game with a Dervish using a guisarme. She has whirlwind attack, which with dervish dance basically means you're hitting every enemy you can get within reach of once (until you run out of movement; have to move 5 ft or more between attacks) in a turn as you dash by. She also has the Elusive Target feat, so rounds she isn't whirlwind attacking, she can purposely provoke AoOs for moving and when the foe misses, get a free (NOT an AoO, just free) trip attack on him. So her whole fighting style works around movement. If the game had allowed more sources, my original dervish idea was also with WWA, but Duskblade as the base class, so I could "hit every enemy on the screen" AND deliver a touch spell on them.