After a discussion for a different game, I became intrested in seeing the differences between load times for Unmasked. This is what I found: Note that the footage reviewed was at 240p via an S-Video cable for each system.

Nintendo Wii (Nintendo GameCube Backwards Compatable) Model No. RVL-001(USA) 443 frames to load "Shuddery Showdown in Chinatown" hub [14.78 seconds]

Nintendo GameCube Model No. DOL-001(USA) 458 frames to load "Shuddery Showdown in Chinatown" hub [15.29 seconds]

Sony Playstation 2 Model No. SCPH-50001/N [NTSC][U/C] 460 frames to load "Shuddery Showdown in Chinatown" hub [15.35 seconds]

Of course, I was only able to test with the systems and discs I have, as I lack any sort of Xbox system and am unfortunate to not have a launch edition Playstation 3 (rumor has it that this system is superb for speedrunning most if not all PS2 titles). Hopefully this information will be of use.