DPF has posted his draft submission on Barbara Stewart's Electoral (Reduction in Number of Members of Parliament) Amendment Bill. It's far more thorough than mine, going into details on the size of our Parliament compared with various overseas jurisdictions, as well as the size of the talent pool for the executive and executive domination of the legislature (arguments originally made by the Royal Commission on the Electoral System in support of a larger House). If you're considering submitting on the bill (instructions here), it is well worth reading.
Update: Lewis's submission is here. He focuses on the referendum aspect rather than the effects on MMP or pros and cons of a larger House, but reaches the same conclusion: this bill is a crock.
Speaking of which, its painful having to be so polite in these things. I'd far prefer to be able to say "I reccommend that this bill be burned, then the ashes placed in Te Papa as a monument to stupidity", but I suspect the politicians wouldn't like it.