Huge quantities of quiet devices

I've got a greenfield job to set up a network with a large quantity of industrial switches. The plan is to have 6000-8000 devices connected to this network, all within a few hundred metres. Each device is a quiet and well behaved microcontroller with wired ethernet. They'll each be shifting mere kilobytes per hour. Let's assume wireless isn't an option.

I can handle layer 2 easily, but what should layer 3 look like? I'm torn between allowing many/all of the endpoints onto a very large subnet and dealing with any broadcast malfunctions when they happen, or staying strong with the old "If you think you need larger than a ~/24, you're probably doing something wrong" viewpoint and creating at least 32 different VLANs. Then what, just creating 32 SVIs on the core switches, pointing them to the central DHCP server, slapping the same ACL on each of them and calling it a day? I'm sure that'd "work", but it feels dirty somehow :) Or maybe it feels too easy.

There will be a few other elements to the network. A few servers, a few workstations, some internet, etc. But the bulk of it will be those microcontrollers.