Does the large Single Speed laptop sleeve hold a macbook pro?

I'm debating whether I should purchase the Single Speed XL bag that's on sale at Timbuk2.com or try to find a used large version. I currently have a Powerbook G4 15" laptop that I know will fit better in the large laptop sleeve but I plan to someday upgrade to a Macbook Pro 15" and I want to be able to keep my sleeve.

I know that the Single Speed line is discontinued (much to my dismay) so I'm scrounging for the last few sleeves out there and time is of the essence!

Thanks,

~Sarah