Nice one! I think you have come up with a very clever integrated solution using the PCB as various structural components. I also like the method of mounting the servo horns. Of course they may not be as strong as screws, but it makes it so much simpler, and reduces the number of necessary fasteners.
Your instructions are also very good too - they give a very good amount of information, e.g. the LED orientation, servo pinouts etc.
Does the large-ish number of individual PCB bits (e.g. the separate voltage regulator board) add to the cost of manufacture?
May I make a suggestion or two? They are very much in the spirit of constructive criticism.
[1] The instructions .pdf file is great, but it's a huge file. A "reduce file size" operation in Acrobat for me reduced it from 16.1MB to 7.6MB. That's help your server yeah?
[2] On your website and this post refer to the micro controller as a "AtMega163", but the instructions call out an "AtMega168". I assume you are using a '168 - the '163 is not pin compatible. Worth updating the website to avoid confusion.