Tracking addresses known to be owned by MtGox, redditors found traces of over 200K btc's belonging to Gox.
http://www.reddit.com/r/Bitcoin/comments/1z3cni/proofs_that_gox_have_at_least_200k_btc/
https://pay.reddit.com/r/Bitcoin/comments/1z30q9/gox_has_at_least_50000_btc/
I have not lost any btcs on gox, however its very hard for me to believe 750K btcs were simply stolen. Malleability can not be an explanation. I also think there is no way that these many coins were stolen back in 2011, and Karpeles was able to operate Gox for so long without major hassle.
Somethings don't add up, and I think this recent discovery hints that there could be more than theft. If verified, this actually goes along with 2 other potential theories:
a. The keys are not lost, but time-locked (and somehow they may still be stolen)
http://www.reddit.com/r/Bitcoin/comments/1yyrkz/well_technically_speaking_its_not_lost_just_yet/
b. US government has control of GOX wallet
http://www.reddit.com/r/BitcoinMarkets/comments/1z2xo5/speculation_the_us_government_has_control_of_goxs/
I'd be curious to hear your opinions as well.