YES, it's da bawamb!!!
There are actually two Grapple mods for JKII Outcast. I think the only difference is that one is faster than the other. You can obtain this mod by finding a server which has this mod installed.
Unfortunately, the JKII "Join Server" menu is not setup to search for games using the Grapple Mod. To find a game through the J.S. menu you have to click on each listed server, individually, and then click "Server Info." The Server Info window will list "Grapple Mod" if it's in use. This is a lot of work if you ask me and I hope that Raven, Lucasarts, or a third party developer, releases a patch to increase the "Join Server's" search menu capabilities. I'd like to be able to search by Server, Gametype, Players, Map, and MODS.
A second option is to use Gamespy 3D, or Gamespy Arcade, to search the JKII servers. Gamespy allows the user to search by Mod. Look for "Grapplemod" under gametype in the search menu.
Finally, I normally install the Grapple1 mod when I setup my server. If you e-mail with a time you'll be playing, in the next few days, I'll send you the server name and/or ISP address. I normally play anytime between 9PM and 2AM nightly.