There's plenty of good, cheap, U.S. multiplayers so I'll stick to those.  Actually, I honesty don't think you can really go wrong with any U.S. multi-player title.
I would just mix up your genres a bit.  Since you already have Bomberman, maybe wait on Battle Load Runner because it's so similar (it is totally great though).  
Shooters:  Ordyne, Areoblasters, Monster Lair.
Sports/Brawlers:  Battle Royale (5 players), Hit the Ice, Power Golf, and World Sports Competition (5 players) are all light on the rules and easy to learn.
Closest things to U.S. beat-em-ups:  Cadash, Shockman.
Platformers:  Buster Bros, Parasol Stars, Bonk 3.
Puzzle/thinking:  Chew Man Fu, Splash Lake, Klax, King of Casino (seriously makes me what to gamble).
RPG (besides DE2):  Double Dungeons!
Racing:  Final Lap Twin, MotoRoader (5 players)
Modify your TurboTap here!:  
http://www.pcenginefx.com/forums/index.php?topic=2893.msg36307#msg36307