Add custom post fields


I'd like to add custom post fields specifically for some forums:
1. Upload an image or select from webpage (webpage posted by user would load all images on the page and let user select which one applies)
2. URL
3. Predefined tags/categories that the post fits into.

In the end the message will be formatted accordingly. Therefore avoiding the messy thread starts that some of my users post sometimes.

Is there an addon that even begins to fit this description or a planned feature?