for the majority price is a big issue BUT with low price comes a need for high turnover which won't suit most high street independants.
what I think would work really well (in theory at least) is a pop-up bike shop. think lay-by butty van on a grand scale and your halfway there. You could turn up at the same locations each day (mainly weekends & bank holidays) on busy local trails turn up at race days or big organised rides & serve the people who actually cycle while they have their head in 'bike mode'
you could take an old school double decker bus, seal off the front passenger door & leave the rear step as the entrance, till by the front door & have a galley style walkway with the stock in display cases down either side of the bus & enough room for a couple of people to get past each other on the walkway. go upstairs and find more stock, frames, bikes etc. and for the grand finale tow a trailer / caravan that acts as a mobile workshop behind you for trail-side repairs & upgrades for your customers.
It could work in the right areas but it would never get enough trade in a couple of days to make a good enough profit to survive.