The Sensor rules on page 445-446 note that sensor systems and sensor arrays can be placed into almost anything with capacity. The sensor housing list on p446 spicifcally lists Cyberlimb with a max sensor rating of 5. It also lists headware as 2, so I guess sensors in cyberskulls are bit more limited. That seems to make it possible to install MAD scanners, Cyberware scanners, cameras, directional mics, laser mics, etc into a cyber arm, hand, etc.

There is some overlap here with existing cyber sensor systems, like Ultrasound and olfactory. I assume the sensor system on page 446 are external sensor systems that are not expressly integrated into your perceptions. You don't actually smell with an olfactory sensor the way you do with an olfactory booster, and an ultrasound sensor doesn't let you replace your normal vision with ultra sound. Also, of course, the sensors can only be built into limb capacity, not implanted directly into the flesh.

Still, if your looking for ultrasound, spending $500 for a single rating 5 Ultrasound sensor system into a capacity 1 slot of your arm, hand, or torso capcity is lot more cost effective than $60,000 at capacity 2 that a "real" headware ultrasound sensor on page 452. If you have an image-link, I don't think you loose out on much having it as a separate sensor instead of a real implant either.

I would say that it still qualifies as a Real Implant, though.

Nice pun

And having some sensors in a hand could be handy for 'peeking' around corners maybe...

Didn't 4th allow cybereyes in cyberarms so you could peep around corners?

Yep, you could put them in the palm of the cyberhand, but you also had penalties for multivision unless you closed the main eyes, then you only had to deal with lack of depth perception.

There was a short lived run on cybereyes installed in the fingers, but there were a variety of issues with these and after the infamous 'ProctorDoctorCam' scandal, they sort of fell by the wayside.