Yes, use Canon Digital Photo Professional! haha, that's the only easy way I know of. It uses different algorithms and often the default raw processiing is very similar to the jpeg - punchy, deep reds, nice greens, oversharpened (this can be dialed down)
You should be able to reproduce Canon DPP processing easily in LR. Please provide a few more details on what you mean by "no luck" when adjusting your CR2 image files in LR to match the "in-camera" processed JPEG. Information that would be helpful are the Canon 5D MKII camera settings you are using, such as 'Picture Style', 'Highlight Tone Priority,' and 'Auto Lighting Optimizer.' LR's default develop settings do not automatically apply these "in-camera" settings like Canon's DPP application. You can however create your own custom Camera Profile presets to include the equivalent processing settings required in LR to "emulate' them. I have a Canon 5D MKII and my JPEGs shot using the 5D MKII 'Standard' 'Picture Style' setting look virtually identical to the CR2 files when using LR's 'Camera Standard' camera profile default settings. Are you selecting both the CR2 and JPEG image files to use the same White Balance settings (i.e. As Shot) and 'Lens Profile Corrections' settings? Have you changed your camera's 'Default Settings' in the LR develop module ('Set Default Develop Settings')? Any changes made to the LR default raw file Develop settings needs to be applied to the JPEG files. By 'default' LR applies no Develop settings to JPEG files imported "next to" raw files.