I am a local at this bouldering area: All I can say is that this boulder is soooo intimidating with its steepness, micro crimps and height - just crazy! So big congratulations to Rok for this ascent!
For reference:
First ascent in 2001! by Klem Loskot: https://www.youtube.com/watch?v=J8fPPAJ77ZM
Second (or third?) ascent by Nalle: https://vimeo.com/63921461
Not that uncommon, they even have names...monos.
Check the holds out on Action Directe in this video https://vimeo.com/6848413 (note though that this is edited footage and whether Rich Simpson's actually managed to do the climb has been questioned).
I have one of these. It could work!
Also, you don't need a special doodad to make great videos. Just a decent cam and a lot of creativity/hard work.