Not really anything big, but I tested the Rage + Substitute glitch myself since you had asked for someone else to confirm it. I used a female Beedrill for my testing, with Pursuit and Twin-Needle as its other two moves.
The battle went like this:
Beedrill use Substitute. *Sub appears as normal*
Staravia used Growl. *failed*
Staravia used Quick Attack. *Sub did not break*
Beedrill used Rage. *Sub slid out, attack proceeded as normal, Sub slid back*
Beedrill used Pursuit. *Sub did not slide out as the attack animation occurred*
Staravia used Tackle. *Beedrill took damage even though it still had the Sub sprite*
So it appears that there truly is a glitch with Rage and Substitue + other moves, and it's not limited to just Kangaskhan.
I wish I could've provided more information, but unfortunately I have no WiFi access here, nor a second DS and game. ;_;