Now could someone please give me a tiny camera with a weblog client in it? A treo? A sony? I don't really care. If it has decent memory it can cache everything and upload it at the next wifi connection, so as not to eat up cellwidth or transmit insecurely.

AvantGo has a neat trick for that: you know how the web is stateless? That means you can queue POST requests for later transmission. For that matter you can queue any http request, if you're dealing with resources that you have an exclusive lock on, or creating brand new ones.

That feature has to be part of the client, but that's not hard.

The request queueing webservice must already exist?

Send an encapsulated http request (including headers), and a time, get back an event id. Then you can run checks against the event id to discover the response.