Here are the CameraSize stats for K-x vs. SL1 (Note that the K-m/2000 was the same size as the K-x):
■Pentax K-x is 5% (5.7 mm) wider and 1% (0.8 mm) taller than Canon Rebel SL1.
■Pentax K-x is 3% (1.9 mm) thinner than Canon Rebel SL1.
■Pentax K-x [581 g] weights 43% (174 grams) more than Canon Rebel SL1 [407 g] (*inc. batteries and memory card).
■Pentax K-x dimensions: 122.5x91.5x67.5 mm (camera body only, excluding protrusion)
Canon Rebel SL1 dimensions: 116.8x90.7x69.4 mm (camera body only, excluding protrusion)
The Olympus E420 the smallest DSLR ever made:
■Olympus E-420 is 11% (12.7 mm) wider and 0% (0.3 mm) taller than Canon Rebel SL1.
■Olympus E-420 is 24% (16.4 mm) thinner than Canon Rebel SL1.
■Olympus E-420 [445 g] weights 9% (38 grams) more than Canon Rebel SL1 [407 g] (*inc. batteries and memory card).
■Olympus E-420 dimensions: 129.5x91x53 mm (camera body only, excluding protrusion)
Canon Rebel SL1 dimensions: 116.8x90.7x69.4 mm (camera body only, excluding protrusion)
If we use these figures to calculate volume, we see that the K-x/m/2000 were similar in size to the new Canon. The main difference is that the Pentax has a fantastic sculpted grip. It is clear that the Oly is the smallest DSLR ever made:
Pentax K-x = 122.5x91.5x67.5 = 7.57
Canon SL1 = 116.8x90.7x69.4 = 7.35
Olympus E420 = 129.5x91x53 = 6.26
http://camerasize.com/compare/#229,448 http://camerasize.com/compare/#206,448
The K-01 is smaller than any DSLR:
121x79x59 = 5.64