If you look hard enough through CP press releases and so on, you will find that they are receiving two more 767-300's this year (leased) in order to replace the DC-10's. And it isn't a rumour, its an official press release that said this. I think 777's are out of the question for them, although any aircraft at all look pretty much out of their ability.
As far as DC-10's being repainted, I heard they wouldn't be. But if CP hangs on as an independant carrier, it could be possible. I highly doubt it will ever happen, though.
As a side note, when AC regenerated 3 of their L-1011's a few years back, they were used for about 2 years in the current AC livery. Those L-1011's were, in my opinion, particularly beautiful aircraft in that paint scheme. However, I really doubt that the new CP colours would look very good on a DC-10. From any photo's I've seen, it looks pretty funny on a 763. I would like to see it on their F28's, too, just to see how it looks. I did rather like it on the 732's and Dash-8's.