Actually, what you're looking for is a way to create a table...table data..table rows...etc. A frame or iframe loads a whole other document or file into an existing page where you insert the code.
Yes, I design websites for a living.
I have seen other forums using BB code that use ' tablebox ' and/or ' table with mrow and col ' to create tables. I've also seen a few signatures with boxes so maybe there's another way around it. If I can find those again and view the source i'll be sure to come back to post how it's done.
I would love to have more control as well.