I'm currently working on a project at my university where we try to build a proof-of-concept-app (android) for indoor navigation with focus on wheelchair-users and their needs. Wheelchair-users have special needs as the width of a door might be to small for the wheelchair, stairs are not usable, ramps might be too steep, find an alternative route if an elevator is 'out of order'. We are still in the planning phase and currently evaluating what technologies we will use. To create maps of the buildings we will most likely use IndoorOSM-features . The plan is to create the building-maps from emergency-maps (German Wikipedia ) if we don't get better ones. We will use those maps as background in JOSM  and draw the buildings with it. As those maps are created by following an official norm I hope, that there is no licensing problem with it as they are not a product of creativity or invention.
There is already a similar app for outdoor-wheelchair-navigation built at our university, but it is not officially published. We are adding this feature of indoor-navigation and both project will be merged. There are already industry-partners, who are interested in this app. This app will very likely be published some time and not just stay a research-project.