I recommend any M3 Replica for the triple shot effect. A foam machete would be nice, Mock Molotov's, Mock PVC Pipe Bombs (It would be nice to modify a cheap electronic toy for sound effect - beeping etc), Bandages (for aesthetic appeal).
If you aren't doing any form of GBB, Perhaps look into an AEP (I'm not familiar with AEP, so no recommended model) or CQB style AEG such as an MP5, MP7, Baby M4, AK47u, or any number of short firearm. For aesthetic appeal you can tape accesories to it or find someone to make you a mock suppressor out of PVC for that "scavenger" appeal. I've seen a few perfectly functioning home-made airsoft suppressors.
If you want to up the ante' a little, swap the mock explosives out for thunder b grenades. Find a nice camping or hiker backpack as opposed to chest rig (or add a backpack to a chest rig).
I'm sure I could come up with more ideas, but I'm thinking of more the average civilian turned zombie hunter instead of some marine style zombie hunter.