I've done a bit of research on the Internet, and it looks like I'm on a dead end.
My goal is to minimize cost, and be able to send and print documents AUTOMATICALLY (may be 10 or 20 pages per day) to a laser printer in a remote office.
The preliminary method is to use: iOS 5.1.1 (JB'ed) with 3G connection, HP (or other brands) printer with AirPrint, iCloud's Documents and may be write some launchd scripts to monitor any new documents in iCloud. May be with other software. I am not sure yet.
By using the cloud, I can upload new docs to the cloud anywhere in my city, and the iOS will be able to see them within a reasonable amount of time, then print it.
But it seems this combo is not workable.
Anyone got any advice on how to make this set up work, or propose other alternatives that requires NO PC or Mac? Currently I have a 3GS with 3G connectivity spare. Need to buy a new printer though.