I did some research in the Rogue service manual:
The OEM block heater is in the engine block (accessible from the outside) and heats the coolant. It threads into the block so I imagine models not equipped with the heater simply have a threaded plug instead. It's not in a very accessible location as it's located just below/behind the water pump which is underneath the alternator. Sorry I cannot provide any pictures.
Nissan does not publish any specs on the heater itself. Typically block heaters are in the 500-750W range.
I've posted part numbers below. If you cannot source a block heater in the US, then you might try to contact an Canadian Nissan dealer.
As for options besides OEM...
Magnetically attached heaters are not going to work as the block is entirely made of aluminum. Magnets won't stick.
Phillips & Temro (AKA ZeroStart) makes a block heater specifically for the QR25DE motor used in the Rogue. Here are the specs:
Part no: 3100007 (comes complete with heater and cord)Replacement cord part no: 3600005 Type: 30mm threadedApplication: - 2002-2007 Nissan L4 - 2.5L (QR25DE) (FWD & RWD) - 1995-2001 Nissan/Infiniti V6 - 3.0L (VQ30DE) (FWD)- 2002-2009 Nissan V6 - 3.5L (VQ35DE) (FWD)- 2001-2009 Nissan V6 - 3.5L (VQ35DE) (RWD)- 2002-2009 Nissan/Infiniti V6 - 3.5L (VQ35DE, VQ35HR) (RWD)- 2004-2009 Nissan/Infiniti V8 - 5.6L (VK56DE)- 2007-2009 Infiniti V6 - 3.7L (VQ37VHR)- 1990-1996 Infiniti V8 - 4.5L - 1997-2000 Infiniti V8 - 4.1L- 2001-2009 Infiniti V8 - 4.5L
http://www.phillipsandtemro.com/
Note: The 2007 QR25DE motor should be the same as the '08-'10 QR25DE. Nissan did not make any changes.
Hope this helps!