Answer:
Some Christian congregations seek to find meaning in the Jewish celebration of Passover by engaging in "seder meals" that try to replicate the Last Supper which, according to some authorities, was a Seder. Whether or not this is true is not the answer to this question. But it does raise the issue of whether or not there needs to be a Christian Seder.
Other Christian congregations create their own "talk feast" (the Greek antecedent to the Passover Seder) that usurp Jewish symbols and imbue them with Christian interpretations. This is totally inappropriate, and many Jews feel insulted when they learn of these (ab)uses of their traditions.
My answer to this overall question is "no" and here is why. The Seder is a Jewish celebration commemorating an event, legendary or real, in the life of the Jewish people. As such, it would be inappropriate for a Christian denomination to adopt the Seder to any purpose other than understanding their own scriptural roots or their Jewish neighbors. I am not sensitive enough to the need of understanding the Seder in context of the Last Supper; I just don't get the connection myself. But if a Christian congregation wishes to know what the Passover Seder is like in order to get a flavor of the context of biblical times, that would be fine.
There is a danger of changing the Jewish Seder into a Christian observance, and this would be wrong. So, no, there would be no need or use for a Christian Seder.