I certainly wouldn't recommend this, but we also did the MCO-BUF 11:00 a.m. flight back in in June '04, and did not arrive at the National Car return area until 10:00. It was very simple to drop off there. No more than 10 minutes.
Gathered our things (2 kids, 5&2, and bags) and went over to the terminal to line up at the check-in desk. When we finally got up to the front it was 10:35. The agent told us the obvious, that we were late, and put "late check-in" tags on our bags. (Which means Southwest is not responsible if your bags don't make the flight and they'll be put on the next flight)
From here we went to security which took another 15 minutes to get thru. By the time we actually arrived at the gate it was 10:55.
I remember this all too well! It was hectic but can obviously be done if you're that late.
Kudos to Southwest however, our bags were waiting for us when we arrived in BUF.
Anyway after all that, we're going back down in 3 weeks and for our flight back this time I'll be there 1.5 to 2 hours befor departure.
Enjoy your trip.
Belle 1627