If HP Beat Extend caused sound stun, thus causing multiple ones do a techable knockdown instead, I was able to do these:
Midscreen
c.LK, c.MK, HP,
j.MP, j.HP, j.HK,
c.HK, HP Beat Extend,
c.LPx2, MK,
j.LP, j.LK, j.MKx2,
c.LK, c.MPx2, HK, A-Train, SSJ
9.3k
Probably need to replace c.HK with c.MPx2 on heavies like BB or Double. Version of A-Train depends on proximity to wall.
Corner
c.LK, c.MK, HK, MP Brass Knuckle,
c.MPx2, HK, HP Beat Extend,
c.LPx2, MK,
j.LP, j.LK, j.MKx2,
c.LK, c.MPx2, HK, HK A-Train, SSJ
9.3k
I'm actually pretty sure there is some way to extend that corner combo considering I barely reach 240 stun by the last A-Train. Tested on Filia and Double so I'm pretty sure this is universal.