See what the Phoblographer reports!
http://www.thephoblographer.com/2011/08/21/review-slr-magic-26mm-f1-4-toy-lens/
This 3rd party "Toy Lens" could be better than Pentax' because it has interchangeable rings in different colours and more importantly, it does have aperture control!
(URL: http://www.youtube.com/watch?v=q_BUXzefB6s)
Of course, the image quality of such a toy lens sucks. But it's just the taste and effect we want to have with those toy lenses and we get the "desired" results without using any digital filter and without the need of post processing! That must be really nice!~ ;-D