Table / File Splitter

I would like to take one table and split it into multiple files tablefile1, tablefile2, tablefile3, ... each with 50K rows. We currently has a package that does something like this; however, it performs poorly. The current package reads 50K rows writes them into a file and then writes the remaining rows into another file. Then it loops and renames the output file that contains (number of rows - 50K) of the last iteration to the input file of the new interation. Even though this works, as the file gets large (in the millions of rows) this rewriting the rows to a separate file is very disk io intensive and slow (over an hour). Ideally, it would be great to be able to split the table into files in 1 pass.

Another possibility would be to use an operation system command to split the file and just have the SSIS package read files and manipuate them (convert them to well-formed XML fragments). I am open any solution that could help me improve the performance. Let me know if you know of any OS file split utilities that can be called from a Job or SSIS.