I've am selling my house via short sale.  I have made all payments except October's payment because the sale is suppose to be completed soon.  BofA advised that they only report a late payment after 30 days of being late and since the short sale will be done before the 30 days, I will close without any 30 day lates.   I will let you know how this affects my credit, but this could be a couple months from now.

As for FHA loans, it is my understanding that as long as you do not have an 30 days lates prior to a short sale, you would be eligible to obtain an FHA mortgage as long as the property is smaller than your original property.