If he doesn't make a post about it on his blog I get the feeling a lot of people could completely overlook it, so I think its worth sharing on here.
...Although I say people might overlook it, he actually updated the Moi dix Mois twitter page with the video, so those who follow Moi dix Mois on twitter probably wont miss it. Heres the post with translations.
MALICE MIZER／追憶の破片 ～ 死の舞踏への特別メドレー at 日本武道館 珍しい資料映像を見つけたのでUPしました 映像は当時のスイッチングです このメドレー展開中々刺激的！ Mana / Moi dix Mois https://t.co/ZlysY8q97T— Moi dix Mois (@M_d_M_official) May 30, 2015
MALICE MIZER／Tsuioku no Kakera〜Shi no Butou special medley at Nippon Budokan
I just happened to find this rare video data, so I UP(loaded) it
The video clips were switching [a lot] in those days
The way this medley progresses is really stimulating!
Mana / Moi dix Mois
If any other news on this video ends up surfacing, I'll update this entry with the details.