The Lord of the Rings: Conquest

This can actually be done in single player.

To do this in single player, choose instant action and select a Hero Team DM map. It'll say if it has it under the Mode select menu. I would suggest the Shire map as it also has Gimli allowing you to get You Have My Axe achievement if you manage to get this achievement fast enough.

Once you have the map selected, you'll want to hit X and make sure the Team Deathmatch Victory Points is set to 100. If it isn't, you may not get an opportunity to get this achievement before the match is over. Make sure to hit A to save the game settings after confirming the setup.

Go ahead and start the match now. Select Legolas as your character and run off and get kills. Try to stay near some of your allies so you don't get completely swamped. This may also give you some chances to steal some kills (and get them stolen, but what can you do). Again, if you get this achievement and still have 30 or so kills left before the match ends, you can switch over to Gimli and try for the You Have My Axe achievement.

This will be a bit easier than the You Have My Axe achievement since you don't have the issue of being a melee character that has no reach.