I know that ScummRev5 can play the CMI SMUSH cutscenes, but I think the SMUSH format changed for Grim so it looks like residual or a capture program might be your best bet. Perhaps try Hypercam instead of fraps.
The Residual source is all in CVS
so perhaps you could get someone to hack out a standalone player with it.
Try a screen capture program on residual when its playing a grim cutscene, if you can get a decent capture with that then there is a wonky and time consuming way to do it. What you'd do is get my Resource File Creator/Dumper
tool and use that to extract the Move Lab file - you'd then get the cutscene that you want to play - give it the same name as the intro file and rebuild the lab. When you started the game it'd play the new cutscene as the intro. Thats massively time-consuming though and youd have to be pretty desperate to try it.