The idea is more for storing all of the supplies that would be needed for an extended stay in a shelter doing emergency communications for amateur radio. I have a couple of big rubbermaid tubs, but securing them to a hand cart would allow them to possibly fall off. I wanted it complete contained.
As for the toolboxes on wheels, I did see those, but their storage area is not as big as I would like.
The cooler I was talking about looks like
this. Go down to the "coleman" ice chest.
This seems to be sortof what I'm looking for. Bigger wheels would be nice, like on the outside.
Edit to add:
Another site for the Pelican Watertight Cases:
Here Edited to add: Sent an email to Pelican. Basically asked for a new line of storage cases with 6" or larger external wheels. Also asked about a custom job.