No. Critical hits deal 150% base damage regardless of how far you fall.
From the wiki: "[a critical hit] deals 150% of the equipped item's base damage (before enchantments or armor are applied)."
If you want to dive into the source code (courtesy of MCP), like I did, this is even more clear. Kind of. A little.
EntityPlayer.java, inside the function
attackTargetEntityWithCurrentItem(Entity targetEntity) (which does precisely what it says on the tin), we can find the code that controls how much damage the player deals to other entities. The critical hit check happens on lines 1330-1335:
boolean var5 = this.fallDistance > 0.0F && !this.onGround && !this.isOnLadder() && !this.isInWater() && !this.isPotionActive(Potion.blindness) && this.ridingEntity == null && targetEntity instanceof EntityLivingBase;
if (var5 && var2 > 0.0F)
var2 *= 1.5F;
var2 is the base damage to be dealt before enchantments are applied.
var5 is a boolean, set to true if the player is falling, not on the ground, not on a ladder, etc. The code never checks how far the player has fallen in any capacity other than to see if the player is falling at all.