Portable Baptistry Woes

Well we are getting a portable baptistry for the new church. There are a lot of plusses to a portable system. Obviously the biggest one is flexibility. We could utilize it throughout the church (ie a special youth baptism service in the youth wing), we can use it in multiple locations in the worship center, and could even take it off site for church picnics etc. The problem is there are just not a whole lot of good options out there. I'm surprised no one has come up with a good system. We even checked with a local pool and spa place to see if they would custom build something for us. Nothing. I have a clear favorite out of the three choices below but am open to any votes you may have!