This grid river/activity setup is incredibly alluring to me.  How would one go about doing this? Rather than a theme, wouldn't a plugin suffice? Or can the core code be simply modified (I understand that's not recommended).  Any advice would be tremendously appreciated. 

I would also be interested in working with you to develop such a thing.  PM me with pricing and whatnot.  If you are unable to, let me know that as well.  Thank You [cim]!

I wouldn't want to modify any parts of the core. Making a grid theme is very easy but it's also very very time consuming since it has to be affect core plugin's pages/views and future plugins with custom pages/views. If you want to work something out then PM me.

Hey wait for me!! I want in

Seems like this is in demand, I'll consider it once my time frees up.

I'm currently working on a profile cover plugin with ajax support, here's a preview:

This is really nice. Will you be releasing it to the elgg community or elsewhere?

Egg community of course but the profile won't look like that, it'll only show the cover photo.