AndreaMG
human eye cannot tell the difference of videos above 60fps
Bullshit 
It is strange to talk about analog eyes with digital measures. Human can watch to moving object on screen and more fps at screen gives more sharpness to the object. It is true at any refresh rate. Even 1000 fps.
Real world have infinite fps. 
some of you interpolate to 100 or 120Hz screens, do you see any difference by doing that?
Yes. I have one: Viewsonic VX2268wm (1680x1050 22" TN-120). And I see the difference. And many other people see it. Especially the gamers. Difference in sharpness in motion.
settings
I will describe it later. It is not easy to describe to easy understand.
While playing 1080i50/60, if in Lav Video Settings is checked "video mode" you have a 1080p50/60 deinterlaced picture, SVP shows 1:1 convertion and does nothing even if option "processing of scene changes" is set to blend adjacent frames right?
There are no relations between option "processing of scene changes" and 1080i50/60 format. Do you understand what you wrote?
In you opinion for 1080i50/60 videos is it right to deinterlace them in "video mode" wihout SVP?
Of course. It is necessarily for all PC (progressive) monitors. Both With SVP and without.
I do hardware VA-deinterlace of 1080i50 video to 50p and after use SVP to get 60 fps. And I can do it all in the real-time. Interlaced video and SVP - it is possible (in Russian)
In this second case to obtain smothness you have to deintelace in "film mode" and then intepolate the resulting 25p/30p video with SVP (Doctor Who BD 1080i50 for instance)
No. In case with broadcasting interlace (telecine) you need to do IVTC with decimation. (NO deinterlace).
The aim to get source framerate (23.976, 24 or 25 fps). View telecined video with smoothness (in Russian)
You need to save video at source framerate and then you can use SVP.
in Russian topics you can use google translation and view the pictures. They tells more than just words.
