Sounds like you have the right approach. You would be wise to start off small and get some runs on the board with small retail prior to committing the resources required to get into the big box world.
As a big box retailer I am always looking to ensure that I am working my store real estate to an optimum level. Your point of sale stand will have to drive sales. Think of it like you are renting space within the big box. You need to make your return on that rent work. That is how the buyer will be evaluating the resources (space) allocated to your pos.
Once you think you have a good execution before
you commit to anything get into the buyers office and find out what constraints he has on point of sale display collateral. There will be guidelines and these will no doubt change from retailer to retailer.
Use you size and your "newness" to your advantage by getting into the buying offices and asking for advice. Buying offices are full of egos (I know I have one too) and you will probably find one of the industry wont be able to help themselves and take you under their wing.
Good luck and keep pushing forward. Remember you know more about your product than anyone else.
The Marketers Mechanic