Is it possible to build a small wifi enabled device that broadcasts an SSID like a router but doesn't connect to the internet? I want to build a personal device that holds 16gb of memory and that when connected to shows a webpage/landingpage but doesn't connect to the internet. Are there any tutorials out there similar to this or any information on where to start?
Of course it is possible. Broadcasting SSID is not only the feature of (wireless) routers but wireless access points in general. Wireless access point can be also a router (like square is also a rectangle, but not every rectangle is square). You can for example: - take small computer with wireless card and make it to be access point, - take any typical wireless router and connect your device, but not connect to the internet (it will work).
There are many options. The best option depends on what you have (device), how much you want to invest and how are your "computer skills" ;-)