This papercraft model of the Dai-X, built by Akama Akama was displayed at the 2017 Wonder Festival in Japan.
To me, it looks to be around 60cm tall and I really like the way in which, when displayed at the festival, they got the model striking a great pose.
Most of these photographs were found on the Japanese Twitter:
#xbomber hashtag on Twitter
From these, you can see the various stages of assembly.
There appear to have been at least two Dai-X models built as well as various Gundams and a VF-25F Valkyrie.
The model appears to have been designed in software and then printed as a series of templates that can then be cut and assembled.
Andy Thomas - Dai-X
Andy Thomas - X-Bomber