This list is slightly out of date (Eagle won't be on it anymore, Livingstone has been replaced by a guy called Darren Williams, a Corbyn supporter)
http://www.labour.org.uk/pages/labours-national-executive-committee
When you look at it, you see a fair bit of support for Corbyn, he'll have a lot of people fighting his corner. It would be no surprise should the NEC (quite rightly imo) decide that Corbyn should be on the ballot.
There are also some NEC elections coming up for Labour Party members. Those who support Corbyn should know (and if they don't, there's very clear guidance on who supports Corbyn) who to vote for in these. Then I'd guess, at party conference, there will be some changes/clarification to the rules so this kind of sneaky bullsh1t won't come up again.