This wiki article has a nice list of Commuter Rail networks in North America, however it doesn't specify power sources. Shouldn't be to hard to run thru the list and find out.
There are a few which also may or may not classify as "commuter rail'. For instance NICTD (formerly Chicago South Shore & South Bend) refers to it's self as an 'Interurban' line, not a commuter line, although most places list it as a commuter line. And in reverse you have the SEMCOG line going in here in MI, which calls it's self a commuter line, however it isn't always classified as that (usually listed as a 'regional line').
peter
PS; if you want to include the few Canadian commuter lines, AMT runs some electric service.