Wouldn’t that be a great bonus to either Rock Band or Guitar Hero? I remember that there was a remix of the Halo theme available for Guitar Hero and that the Portal song “Still Alive” was made available for Rock Band. I would have such a blast rocking out to the Ghostbusters theme song!
On a musical level…there’s really not much to the song. I think the guitar and bass parts would be too repetitive to be fun. But…you will be able to create your own songs in Guitar Hero World Tour, so I would expect we’ll see some fan soundalikes or re-creations. If they give us the tools, we’ve got the talent. 
You might get some traction by posting in the Rock Band forums too, see what other people there thing. The devs do read those suggestions.
well actually guitar hero 4 you will be able to upload your own songs from your MP3 player. So then you can have your very own GB theme on GH4
Mmm…not quite. You will be able to make your own songs with the song creation tool (which is MIDI based), but you won’t be able to simply import an existing sound file. Sorry. 