The Dexion website has a complete list of their racking options listed under the "products" tab. This includes their pallet racking, vertical storage, shelving systems and cantilever racking.
Cantilever racks are industrial shelving that are used to hold tubes, bar stock or other long items. If one is wanting them at a discount, one might find a company that sells used equipment such as AA Surplus or American Surplus. They are also available through industrial supply companies such as Grainger or McMaster Carr.
Depending on what type of storage shelves you are referring to, stores like Lowe's and Home Depot are typically the best option. Both stores provide you tips and various usefully information for self assembling projects such as your shelving. They also have the type of shelving more appropriate for a garage, compared to a place like IKEA or a furniture store.
To find the reaction force of a cantilever, you can sum the moments about the fixed end of the cantilever (often where it's attached to a wall or support). The reaction force will balance the external load applied to the cantilever to maintain equilibrium. Equation of equilibrium can be used to solve for the reaction force.
You can kind commercial cantilever racks here at http://www.lkgoodwin.com. They are very knowledgeable and will help you find the rack right for you.
To find the magnitude of the force acting at the end of a cantilever with a distributed load, you need to calculate the total load or weight acting on the cantilever. This can be done by integrating the load distribution over the length of the cantilever. Once you have the total load, you can use equilibrium equations to find the magnitude of the force at the end of the cantilever.
There are many places online to find information on how to properly hang shelves. FamilyHandyMan, StackExchange and Home-Shelving-Guide are also great places to go.
You can find all sizes of bathroom shelving at a major home improvment store.
You can find information about garage shelving ideas on the following site: http://www.sears.com/shc/s/c_10153_12605_Tools_Garage+Organization+%26+Shelving. They have a good selection.
In order to find laundry room shelving, you must visit a home goods store and see if they stock any or check your computer to see if it comes up with any places to get some shelving units.
Shelving Online offers various types of shelving that you can purchase online. From wood to metal and many other materials. Here is the website to get you started: http://www.shelving-online.com/.
You can find warehouse shelving at shelving-direct.com. They have all sizes and also prices on each shelves. The website has different shelving to choose from for your business needs.