I've only started getting into Wordpress since November of last year and have been desperately trying to learn how to develop with it because I think it's great. I discovered the Hybrid Core a couple of weeks into my 'education' and I love the whole principle behind what you've done - not to mention the structure and the whole ethos behind it. However, I think it's really important that you need to learn to walk before you can run, so rather than diving into creating themes using the Hybrid Core, I figure it's a lot more prudent to start as simple as possible, even though I sometimes forget this and find myself skipping stages A and B, only to get bogged down in C without having a clue of what I'm doing.
Anyway, although I'd found this site quite early on also, today I decided to work through a tutorial developed by a guy called Ian Stewart over at themeshaper.com (http://themeshaper.com/2009/06/22/wordpress-themes-templates-tutorial/) and I've got to say it's really helping to make few principles very clear. I noticed a couple of references to yourself in some of the comments and wondered if you had any connection to Ian Stewart? Additionally I realise that the tutorial was uploaded in 2009 and acknowledge that there must have been a load of updates to Wordpress since that time, so although the tutorial seems to work fine for me on my local server, I'm wondering if a lot of what it teaches might be outdated now?
Apologies that this thread is not directly related to Hybrid, but if anyone is starting out with Wordpress from scratch (provided the tutorial isn't too outdated) I'd recommend it as a starting point.
Really looking forward at getting good enough to work with Hybrid though, and thanks for all your efforts to-date in making such an awesome framework.
PS. I also came across this article today which goes on about code-bloat and too many database queries in commercial wordpress themes and frameworks - something I'd never really considered before. It's an old-ish article, but in the comments section you'll find that Hybrid was rated at the top of the tree for fewest database queries - so congratulations :)
Edit: Whoops - and the link: http://foliovision.com/2011/03/28/paid-wordpress-themes-woo-vs-elegantthemes