No concrete plans yet.
One direction it could go is to have a second pyramid of another 45 challenges, making a total of 90 challenges. You won't see this second pyramid until you've conquered the first one (of 45).
But the problem is the creation of the challenges. Here're two possible scenarios:
1) Each member after 45 contributes a challenge to the second Pyramid. The challenge will be named after the member.
2) Status quo - coding done mostly by me but with most challenge ideas contributed by members.
Oh, but I'll make 45 so hard obscure that a second Pyramid won't be necessary ;)