Yep. M55 is at a southerly declination. The good news is that you can get it when you come on down for the Syttende Mai Star Party or the 3rd Annual Star BQ.
M83 is also a very southerly Messier object in Hydra. But that is easily caught from Eagle Bluff. I'm pretty sure that we saw it at our last Messier Marathon. It is a very nice object in an 8" scope, I can only imagine how beautiful it would be in larger aperature or by imaging.
M100 is easily doable, BUT, you have to star hop east of Denebola in Leo to a triangle of Messier objects. M100 is the westernmost of the three, and each of them have a noticable star in the FOV.
You could get all three in February if you wanted to stay up that long.