Hidden Post - Thank You - Reward

[Hoang Tu Ao Den]

I'm very interested in the Post Thank You Mod . However, I want know if there is modification to that Mod or another Mod that can do the following:
1. Do what the Post Thank You Mod do.
1. There's a hidden text tag that we can use, we user use this tag, a picture will appeared showing the text is hidden.
2. In order to see the text, user has to be registered longer than 30 days or have the reputation of xxx or more , or ... has 50 post or more.

Thank you.

Any idea ?