iWeb from Apple has its limits like all tools. (e.g. the home URL encoding) Please suggest best places on the web of examples of extending and work arounds?
Despite my being a big Mac fan, I haven't really used iWeb all that much. When I was looking into it, I checked out Apple's own website: http://www.apple.com/ilife/tutorials/#iweb. Their resources page gives links to other websites as well. Lynda.com is a fantastic resource, and they have a series about iWeb '09. Another site mentioned was macProVideo and their iWeb trainings.
Since you mentioned you wanted examples of extending iWeb, macProVideo's Advanced iWeb 09 might interest you. At the same time it does cost about $20US, so I don't know if you wanted to put money towards this or not. A blog that, from what I've seen, has some pretty in-depth tutorials, tips, and tricks about iWeb is allAboutiWeb.com. It deals with some of the more nitty gritty HTML tricks to pump up your website.
There seems to be very little information about pushing the limits of iWeb out there. Hopefully that helps out.