No, that's out now, as they've already started building the station box, and have already launched the TBMs from Sheppard East station. I suppose they could build a huge curve stretching way north - but they won't' it was never the plan.
It's a shame though, that they didn't angle both lines northeast/southwest at Sheppard East, to facilitate simple transfers like at St. George (or even like Lionel-Groulx and Snowdon in Montreal - which is a brilliant design).
yes the Sheppard East station box placement being north of Sheppard is a bit of a missed opportunity unfortunately.
i'm no engineer, but couldn't it still loop around to connect to a Line 4 east extension despite it's awkward placement if there's enough desire to make that connection happen. the one seat trip was a big selling point to getting this Scarborough Subway Extension built in the first place wasn't it? not having to transfer at Kennedy. it might also create a better connection/transfer to Agincourt GO station too.