There is at least one case that involves a pilot taking off IFR in Class G without a clearance. The NTSB decided that doing so, at least in situations where the activity may tend to pose a safety risk to other operations, is careless and reckless even though not specifically prohibited by a FAR.
http://www.ntsb.gov/alj/O_n_O/docs/AVIATION/3935.PDF
this is also true. You should take off from Class G into Class E if you are going to be in the clouds upon entering class E. Because you need a clearance to do so, and it is not possible to get the clearance until you are in class E. So if you are in the clouds, and in Class E before you get your clearance, you could be busted for Careless and Reckless operation.