Bukkit

What is the enhancement in mind? How should it look and feel?

At the moment, even though HCS commands are executed as though the player using the sign executed them, they do not count as though the player had typed the command in chat, since commandhelper aliases to not catch these.

For example, an alias on the server might be "/poke = msg('The sign poked you!')", but if /poke it put into a hidden command sign, it will not be sent right to bukkit, and will not be recognized as a command.

In particular, this issue is important when a command is aliased to a script in commandhelper. You can write complicated scripts in commandhelper (such as to reset a spleef arena), removing the need for other cumbersome plugins. Is it possible to send HCS commands to commandhelper first, as though the player typed them in chat?

Sidenote: Is there a built in method for delivering a message to a player?
I noticed %p is a variable we can use, so there must be some features not mentioned in the main page. What other hidden variables or functions are there?

Try the ChatCommand plugin. Tell me if it fits your needs.

The %p variable was listed on the SimpleCommandSigns description.