Everyone remembers the skateboard weapon icon that was found in the PS2 version, right? Sadly, that was all that remained of the unfinished item, as the model and texture files had been removed before shipping. In the PC version, however, R*^ was kind enough to include the missing bits for us to play with. It's still unclear whether any of the associated animations still exist, but for now, it can easily be used to replace any melee weapon.

Skate or die!

Replacing brass knuckles

Functioning as weapon

In this case, I replaced the combat knife, but it can also be swapped out with other weapons. To replace the knife, find and open default.ide in your /data directory, and replace this line:
335, knifecur, knifecur, null, 1, 50, 0
with this:
335, skateboard, skateboard, null, 1, 50, 0
To replace any of the other melee weapons, just edit the second and third column in the same manner.