There was a time when some cameras (like the Fuji FinePix S7000) used in-camera interpolation to boost the megapixels (from 6 to 12 in that case, I believe)

Are there any manufacturers who still use this trick to make their cameras look more impressive than they really are?

The reason I ask is because I'm writing an article of advice for camera buyers and I want to know if this is still a feature to be avoided, or if it's not worth mentioning because manufacturers have abandoned it. I can't find any cameras claiming to do it, but that doesn't mean that there aren't any.

Are there any manufacturers who still use this trick to make their cameras look more impressive than they really are?

I don't think that it is a trick, but rather a different way of capturing light via the sensor.  I actually think that the Foveon X3 captures light in a more realistic manner than most other cameras out there.

I think that both cameras are known to have excellent image quality, but they are definitely not the type of camera to use for stock sites (since they don't understand the technology).

I am aware of two camera systems.

Fuji Super CCD:

http://en.wikipedia.org/wiki/Super_CCD

Sigma Foveon X3:

http://www.foveon.com/article.php?a=67

I'm not sure if you have seen some of the images taken with the Foveon X3, but they are simply amazing.

For example, check out this image:

http://www.sigma-sd14.com/sample-photo/portrait/img/sd14-po-005.jpg

Or go here for some more:

http://www.sigma-sd14.com/sample-photo/index.html

The Fuji cameras are a problem at iStock.