manual focus screen

If you haven't tried live view for manual focus work then please go and give it a go.
In Live view, you can press the OK button in the middle of the four way controller, and you will zoom digitally into the image.
You can steer the zoomed point around the screen, and using the scroll wheel move further in or out.
With focus peaking on, I've found this incredibly useful for finding and confirming focus on the eyes for example.

Not as comfortable as the OVF, but unquestionably more accurate.
An EVF would be ideal for manual focussing tasks.

Add this one in across the board... Unfortunately a majority of brand name lenses out there (even lenses that cost several thousand) seem to leave certain key items completely missing from lenses, such as...

Focusing scales, aperture scales relating to focusing, etc... Or how many lenses out there still have an aperture ring. Sure there are some compromises for size, weight, etc... But guessing that most cannot bother to place fundamental items onto lenses

Focussing scales have never appealed to me. They're present on the better lenses, but I personally don't use them. I see one new lens came out recently with a digital focussing scale on it...

When my Aperture motor failed, I became acutely aware at how few modern lenses have a dedicated aperture ring. That said, they're not normally required as you can set the aperture in the body. For macro work with a dumb spacer ring, or for timelapse work then you would want them to allow you to adjust the aperture, and to ensure repeatability between shots.

The manual side of things is interesting, as many of the more modern developments of DSLRs are along the lines of metering and focussing. I see little need to upgrade if you mostly shoot in manual mode and manual focus. Sensor abilities haven't increased dramatically in the last 4 years or so, with the K-5 series still punching well today. Increases in resolution haven't really improved abilities much in low light situations. In some ways it silly to have a camera where most of the features aren't used. Even now I tend to use single point centre focus. I have little faith in my Pentax's ability to track a moving subject, and the focus points are only near the middle of the frame anyway. Gets you thinking really about what one really needs in a camera, or where Pentax could improve more etc.

I use a magnifying view finder adaptor on my K30 for manual focusing and the focus confirmation light
and it is usually spot on
Also focus peaking for close up work. I did replace the screen in a K110D with a split screen from china but found I had to remove the shims as the new screen was thicker than the original but it works ok and seems to meter right

Geordie. From where did you purchase said item or do you have a link .

here
http://www.ebay.co.uk/itm/1-08x-1-60x-zoom-viewfinder-eyepiece-magnifier-fo-Cano...