I salivate over the idea of flash & fast shutter, but that would
"technically" give third party manual flashes an HSS function
for free. I hope the Canon-you-know-what-hammer doesn't
touch that.
No danger there. Except for the mentioned Hensel Expert D 250 Speed,
which is a rather hefty studio type mono flash, 99% of the third party
flashes can't dump their stored power within the necessary short time.
Only a few flashes will be able to make use of an extra two or three time
steps due to global shutter. There is room for new flash units as well
which can go all the way up. Flash duration is one of the hardest things
to reduce without giving up power.
This is the flash that I would put to use, I have five of them:
<div> </div> <ul> <li>Max. 250Ws</li> <li>Ultra short flash durations from 1/4000 to 1/10.000 s</li> <li>Shortest flash duration 1/10.000 s from 90-32 Ws</li> <li>Extremely fast flash sequences from only 0.22 s to 0.045 s (4,5-22 flashes/second)
katalog.hensel.eu
And this is the mobile power source that I have for it:
<p><strong>2x Schuko sockets 230 V / 50 Hz</strong></p> <ul> <li>Flash capacity: up to 880 flashes at 250 Ws, 440 flashes at 500 Ws, 220 flashes at 1000 Ws etc.</li> <li>Suited for max. 3 Integra Mini, Integra Plus, 2 Expert D or 1 Speed Max. Please as
katalog.hensel.eu
A 120V version is also available.
This gives me up to 16fps at 64 Ws with several thousand pops per charge.
Manual flash power, all manual mode, of course.
Yes, this narrows down the number of people with enough skills that
are needed to put this to good use. Or those who can fork over 4 grand
for the setup.
I don't think Canon needs to protect their own flashes for this.