Well, it would be possible to have a bill that, as a vehicle--and it's been done in the past--proposes an amendment to the Constitution Act, 1867, that is textually, and also provides for other provisions.
In fact, if you were to look at the Nunavut Act, you would see that it has amendments that amended the Constitution Act, 1867 by adding a senator for Nunavut and representation in the House of Commons. Those were actual textual constitutional amendments. And then it went on to provide for the Government of Nunavut in the Nunavut Act.
So you can have a bill that's a vehicle for that. But this is not what has been attempted here, and I think the government's position both on this and on the previous bills, Bill S-4 and Bill C-43, is that these are independent legislative measures. They go towards a broader view of reforming the Senate, but they stand alone, and they stand on their merits to be voted up or down accordingly.