Sometimes a very small housing is needed in CAN applications.
Here are some examples of micro controllers with CAN. Smallest first.
Fujitsu MB90387, is a LQFP48 7x7 mm. 16-bit microcontroller.
Renesas R8C/23 PLQP0048KB-A 7x7 mm. The R8Cs are actually "little brothers" of the M16C familly.
AT90CAN128 QFN 64 9x9 mm.
AT90CAN128 TQFP 64 16x16 mm.