Wow, more comments and questions...
Slider is just the jQuery cycle plugin here: http://jquery.malsup.com/cycle/
I see you posted your question in the BuddyPress-Hybrid thread. I will reply there.
1. Eh, yeah... the tabs are a custom thing. Basically, I wrote a class to act as a mini "Tab template engine" so the tab layouts are mini templates defined in the class (since the news tab has a different layout than the others). The tab content is generated using a custom WP query that uses input parameters from the Theme Configuration so you can turn the two tab blocks on/off and choose which site categories you want to use for the tabs. You can set up to 4 tabs, define the tab title and select the category.
2. Hybrid Child theme would be nice but as you suspect, there's a LOT of custom stuff in there. We do have in the pipeline to develop some templates for "Sub-sites" on this project so just maybe, there's a cut down child theme lurking somewhere :).
You're right, you wouldn't want to run this on shared hosting. It's on a VPS in Singapore and I replaced the main jQuery to use google CDN. Also, when WP3.0 goes stable, and the cache plugins get updated, we'll be looking at implementing one of them too. I also think that the host has installed APC or similar on our account.
Thanks for your kind words. Much appreciated.