• Would it be possible to include a chest in the mod where coins can go? If you place multiple chests, coins go to the one with the least, then select a random from the ones with least if there's many with the same number(like zero). I like this mod, especially the biter bounty. I have it and rampant going strong, but there's coins falling everywhere!
• I've been trying to put together a modpack where fighting is the main thing. Got this mod, Rampant, ammo loaders and ore changing cheat mod as the key mods. That last one just lets you exchange ores for coins and vice-versa. No actual cheating involved. I've taken out the ore gen to force the currency route and included a starter base with some basic defenses and production(ammo). Oh, walls block spitters is also there. Pretty good combo that's shaping up real nice.

I've slowed down my modding activities for a while now, so in reality adding a new mechanism from the ground up is unlikely. If there was an existing mod which I could pass the coin values to as a remote interface call and it handled distribution then adding it as a new dropdown option is far more likely.
The ground item pickup mod I've seen used with it before to collect turret coins and other mods' biter drops: https://mods.factorio.com/mod/SchallPickupTower