Business Plans

I’m attempting to put together a business plan for a taxi service. There is competition in my local area for such a service. What is the best way to “gauge the market”? I will need a source of capital for this venture and I want to be as thorough as possible when drawing up my plan. I think I have a good idea (this will not be your run of the mill taxi service) but I want to be smart about assessing the feasibility of the business model. How can I figure potential earnings or the demand for this service oriented business?

I have a business plan. However, I feel as though I need a business plan FOR the business plan. For the simple reason that the business model itself is new, I need a way to do the intial targeting of customers.

I’m not really looking for a company who can print literature and build websites. I am looking for a company or person who can figure out how to connect my new concept with customers.

I guess I’m looking for a hybrid between a business plan writer and a marketing expert.

Any ideas? Thanks in advance.