Did you ever receive a satisfactory response to your question about your proposed stand-alone wi-fi hot-spot/server application?
The reason I ask is because I want to do exactly the same thing as you described in your posting. In my case the project would take the form of a black-box (plastic) with a power supply, raspberry-pi (headless) and a wi-fi dongle in "master" mode. I wanted something that would show-up in a list of wi-fi connections (for anyone who is in range) and serve-up a "welcome" page by default if they choose to connect. This might be another pi or a laptop.
Any additional pages/files I could pull from the virtual wi-fi server would be icing on the cake. So far I have had little success in finding exactly what I was looking for but someone has responded to one of my posts saying how easy this is to implement and gives an example of a garden sized network they have implemented themselves. Sadly, the response did not include any technical detail but I have asked if they would provide some additional information since the brief description given seems to be exactly what we are both looking for.
Serving web-pages using the berry web-server software proved very easy but it seems (in its current form) it only works as part of a larger network which includes a wi-fi router.
If you made any further progress with the project I would be very interested to hear about it and like-wise, if I find a solution I would be happy to share the details with you.