I doubt including LEGO in your inventory would be profitable for the forseeable future from a purely sales standpoint.
As to attracting LEGO enthusiasts to your store and building a customer base, it probably would... especially with regular BrikWars type events on a weekly basis. So it might be a good idea to have a few LEGO items inventoried simply to break even on the product while getting more general interest in your store?
If for some amazingly impossible reason you actually outsold WALMART in quantity of LEGO, you might be able to work out a better deal with your wholesaler or even go direct?
