Possible SSD Xbox upgrade card leak from twitter. Unconfirmed obviously at this point.
Ouch if so, but it does make sense given SSD prices.
One of the biggest emerging weaknesses of XSS will be storage. If you have slow internet, buying games on disc to have them ready to install when uninstalled wont be an option.
I think the best option for those with capped or slower internet would be to buy an external HDD for "cold storage" (apparently this is confirmed to be allowed on next gen xbox, which i didn't know) A 1TB seems to run about $45 on newegg.
Still, this is another $50 if you aren't prepared to deal with 512GB by itself (will of course be what, 400 after OS bloat/formatting?).
Realistically this might be the biggest XSS achilles heel.