thereThere is actually a paragon pathParagon Path that can help with this. specificallySpecifically, its utility power
"Ride the Giant Down" target one Large or Larger creature melee one, keyword martial
Effect: you move into the targets space, provoking opportunity attacks as normal. until you leave the targets space, the target grants combat advantage to you and your allies and takes a -2 penalty to attack rolls, and you grant combat advantage to other enemies. any attack that damages you also deals half the damage to the target. when the target moves, you move with it, staying in the same portion of the targets space.
if the target hits you with a melee attack, it can slide you 1 square to a square adjacent to its space unless you succeed on a saving throw.
Special: if you are trained in Athletics, you don't grant combat advantage to other enemies because of being in the targets space, and you can make a saving throw to negate any pull, push, or slide that would move you out of the targets space.
Ride the Giant Down
Daily ✦ Martial
Move Action Melee 1
Target: One Large or larger creature
Effect: You move into the target’s space, provoking opportunity attacks as normal. Until you leave the target’s space, the target grants combat advantage to you and your allies and takes a –2 penalty to attack rolls, and you grant combat advantage to other enemies. Any attack that damages you also deals half the attack’s damage to the target. When the target moves, you move with it, staying in the same portion of the target’s space.
If the target hits you with a melee attack, it can slide you 1 square to a square adjacent to its space unless you succeed on a saving throw.
Special: if you are trained in Athletics, you don't grant combat advantage to other enemies because of being in the targets space, and you can make a saving throw to negate any pull, push, or slide that would move you out of the targets space.
thisThis is the level 12 utility power from the paragon path "Giantslayer"Giantslayer Paragon Path.
thisThis may not be the fix you are looking for, but I thought I would mention it.
