[Kabe]

A spherical cam would be great for creating HDRIs

Fisheyes or other distorted lenses are great for dynamic images

Shift-Lenses are a god send for architectural images, wehen you have to avoid tilted lines.

All of these shouldn't be too hard ti implement

Kabe

[Bubbaloo]

Have you tried using the simulens settings from mxcl?

[Mattia Sullini]

A spherical cam would be great for creating HDRIs
Shift-Lenses are a god send for architectural images, wehen you have to avoid tilted lines.
Kabe

If i understood correctly your wish, i guess you will find it accomplished in the camera param tab, the last two fields named X-offset and Y offset.
Those kind of lenses can usually tilt also, and this produces funny results with DOF...but i think those could be simulated with the lowest F-stop

+1 for lense distortions

[kami]

yes, fish-eye-lenses and a spherical cam would be great.
also a possibility to render planar views could be added. i've read several requests for that and i miss them too.