Here's an alternative viewpoint:If you subtract the vocal, you have to have the melody coming from somewhere, right? I'm not sure that bells are any worse choice than anything else. Electric guitar makes it too rock, lots of keyboard sounds would make it too electronic...what do you suggest that keeps it singer/songwriter feeling? Maybe an acoustic guitar, but that can feel really flat and boring. I'd push back that the bells are still EVERYWHERE and that while we are constantly wanting to be on the bleeding edge, very little of what actually gets used falls into that category. But what do I know? I'm just a spectacularly achievement-deprived wannabe musician!
Sometimes you don't need the melody. Sure all the refs have vocal melodies, and they are supposed to flavor your piece with the right sauce.
You piece needs to have the right vibe so that it could be placed under a scene where something else is happening and give it the FEELING of having one of these refs under the picture. Not necessarily the vocal melody, that would likely compete with dialogue.
When it comes to melody / no melody, a simple strumming part on a guitar can have enough melody to get you started. Make that the focus of your cue can get you started.
Then everything else, the drums, the bells, etc. can be more minimal. Like the strings (?) at the end of the Rob Thomas piece are pretty much holding a pedal tone, not even a chord. The drums aren't a full set, its more of an indie 4 on the floor kick drum (think Mumford and Sons) plus some claps for backbeat. Same with the Fine Frenzy piece. The strings are also pretty minimal in the fine Frenzy piece and the thing that struck me most was the great guitar sound.
Something to consider - like was said by DI - sometimes a great piece isn't the right pitch for the listing even though it seems right when you made it.