I doubt you will find anything under $500, though stranger things do happen! If you are prepared to drive to MKE you could try a YUP fare MKE-MCO. I did this for my promo and squeezed 8 segments out of it for a 50K bonus. MCO-MIA-DFW-ORD-MKE-ORD-DFW-MIA-MCO. Of course you could easily route this as MKE-ORD-MIA-MCO or MKE-ORD-DFW-MCO as you only need 6 segments. My fare came to $590. Note however that you probably won't be able to do all this in one day, so an overnight in MCO will probably be required and have to be added to your cost basis.