How precise do you want your answer?

One thing is focal length stays the same no matter what or how much you crop or do with your photo, so the f/2.8 DOF of a 150mm lens would not be the same after crop as the DOF of a 300mm at f/2.8.

Than you also have the sharpness of the lens, since you make enlarge a part of the photo that would mean the quality of that would also need to be better then the fullframed photo.
And in the same spirit the larger pixel of the k100D is of better quality than a single pixel of the K7 simply because that Pixel is larger but because the K7 has more in the end the quality would be the same and the extra pixels would give you more play room so to say.

So in order to get the same detail in the situation you suggest you would need a 150mm lens that's twice as sharp as the 300mm and the pixels of each camera need to be of the same quality since it's probably neither you can say that the K100D with a 300mm lens would make a better photo than the K7 with 150mm and cropped 50% or at least the k7 and the 150mm lens need to work twice as hard to get the same results.

I know but I never find myself good enough, the one time I entered which I thought wasn't such a good photo I won
I never had the courage to do it again

The current subject is very to my liking though so will force myself to enter something.

Of course but you can print it bigger and so force a different perspective.

At my grandparents place there hang 5 photos on the wall of each of their grand children, I took those photos all around the 100mm and they look good as A4 print. Since they hang on the wall the viewing distance is 1 meter or so I think if you would print them bigger that they would look quite different.

Have you taken so many photos the these two days

Sounds good James, thank you for your support and it sound something Like I could do.
I'm going away this weekend and i probably have a photoshoot a Monday but ain't sure about that one, the photos from there could be used here.

Terry you might be right there about me but I like to know why or why not, it's just not in me to take something for granted.

About the viewing distance it does change your perspective when you come close or use a larger print.
I mean when you stand close the viewing distance from the centre of the photo is closer then the viewing distance from the corner of the photo so your perspective change.
or am I wrong

Just get an DA*50-135 and you have all the useful focal lengths for portrait, problem solved

Focal length they are both okay but they might be considered long when using on APS-C so digital Pentax camera.
As for the aperture, I mostly shoot around 100mm with f/2.8 and that's just right I think.
1.4 (1.8 less so) might be a little too open although that can of course be the effect that you want but you must be very careful how to place the DOF, you most likely should be working from a tripod then or really train yourself how to use it effectively.

If you want cheap there is Samyang with an 85mm f/1.4 lens.
You also have Zeiss with their 85mm f/1.4 Plannar T*
Pentax 85mm f/1.4 lenses of course.
there is also the Voigtländer 90mm / F3.5 SLII, not f/1.4 or f/1.8 but it has a stunning Bokeh if the old one is anything to go at.

MrCynical also has the same messages, don't know if he wants it removed or not

Just an idea but isn't there a way to delete all messages off an account in one go?

Not if you don't use those extra pixels.

It's the same as asking if Ferrari will be faster as a Volkswagen on a public road if you keep on the speed limit both will be evenly fast

So you either use those pixels to have more room to Crop like Tim says or you use those pixels for a bigger print if you don't do that they would be both evenly sharp.

Or they set the x-ray machine to max with the hope they get through it... if they do your film is surely baked like you already said

Just a clear plastic bag with film is the wisest decision, they can clearly see it's film canisters and label them all ISO800 since they won't go through the scanner then.

I wonder if you could hold them responsible if they insist you to put it through the scanner.