Modular widgets

How about a PC board to support things and interconnect and carry the i/o connectors and LEDs and stuff?

So like just make a simple PCB with slots for say, those breakaway header pins, and route the interconnects on that and solder in the prefab modules on the headers?

Yeah I think that could work

Don't forget chewing gum. Chewing gum helps hold things together better. (snert)

That's a really silly suggestion. The real pros use Velcro.

Or duct tape ...

I would think seriously about a small simple board to hold just the parts needed for the specific data reading and collection part, then go bluetooth data to an Android tablet or phone, and do all the storage and fancy display ( if any ) in that. The tablet device already has Computer, Storage, battery backup, charger, etc, which is about 95% of your requirements. Extra storage you can get by sending the bulk data Wifi to cloud storage or a PC/Hard disc.

First, get a big-enough box. Then, put a chassis inside. Every subsystem (batteries, CPU, mass storage, display) mounts to the chassis, and the box supports the chassis and a few I/O connectors, and maybe a window.

Just remember: no loose parts, it ALL connects to the chassis.

'lots of data' can mean big storage, or a WiFi port to the cloud; it might be easier to get a reliable net connection than a reliable SD solution.

Velcro lets you fix your mistakes. Duct tape is forever.

Conductive velcro would have interesting possibilities, for ESD or especially if it was striped conduction like zebra polymers.