I think the ideal format would be graphical and interchangable. There could be templates or symbols that you type into and even positional choices (eg draggable symbols). Being able to decide your own format and display it how you would like is not far fetched. However it probably would require a new module that creates formats. For drag ability the current technology suggests one of the following java, flash, Dhtml or code that parses a final output that can be dragged. Templates would make things easier to add required information to the database fields needed however it may be a bit restrictive.
Just Thinking - maybe someone might give this a try.