Serializing LINQ expression trees

I got simple LINQ expression trees to serialize last night. As I expected, the direct approach is to create a parallel set of expression types for each type in System.Linq.Expressions. With a set of serializable expression types, serialization is a snap. Here's what the code needs to do:

For Serialization

1. Perform partial evaluation on the LINQ expression tree. See this article by Matt Warren for code that supports partial evaluation. See my previous post for why this step is necessary.
2. Map each LINQ expression to a corresponding serializable expression. A visitor class greatly simplifies this step.
3. Serialize the expression tree. I tested with the BinaryFormatter, but I'm confident the DataContractSerializer would work as well with its support for [Serializable] types.

For De-serialization

1. De-serialize the expression tree.
2. Map each serializable expression back to its original LINQ expression. Again, a visitor class is recommended for this step.
3. Use the expression tree.

As of now, my code supports lambda, parameter, constant, methodcall, and a convert expressions. To support the rest, it should be just a matter of implementing the remaining expression types as the proof of concept worked.