Create a simple game for our website for clients to use

We supply & install systems such as pallet racking & shelving for warehouses in Australia. We'd like to create a simple & fun interactive 'game' for our clients on our website: the idea is to allow our clients to enter a warehouse size (e.g 20 metres x 30 metres) and it comes up with a blank warehouse floorplan. They can then drag & drop bays of pallet racking & shelving into the floor plan, specifying the height, shelf levels, width & depth they require for each bay of product. Then if possible we'd like to allow the client to click through to a realistic "walk through" of their new warehouse design - so like a 3D walk through as if you are really walking into the warehouse. We would need to allow for dropping additional items like 'Entry way', 'Office area', 'Floor storage area' etc so it is more like their real planned warehouse. If our budget allows it, we were also envisioning allowing the clients to select either a 'Forklift' or 'Storeman', then be able to use their arrow keys to move the forklift or storeman around the warehouse, and maybe allow the option of removing a pallet from the pallet racking using the forklift (something simple like 'Press Space bar to unload a pallet') for more of a 'Fun factor', or 'Press Enter and the storeman can pick a box off the shelf') Any ideas would be much appreciated, We look forward to hearing from you. Our website is [login to view URL] if you would like more of an idea what is involved.