To answer this older question: No, there seems to be no business plan template in LaTeX available. There is nothing on CTAN and I only could find unsuccessful forum / usenet threads about the topic:

https://groups.google.com/forum/#!topic/latexusersgroup/Dyz3Vyk7ZVk
http://www.latex-community.org/forum/viewtopic.php?f=4&amp;t=4659
http://www.latex-community.org/forum/viewtopic.php?f=4&amp;t=787

In my experience this kind of documents is done by people which hardly use LaTeX. Even so it is normally done by a group of people which collaborate on it and as long not everyone is using LaTeX this doesn't work easily. I know it from my patent submissions where it is a little similar.

Even if someone would have written a good business plan with LaTeX it is a lot of work to turn it into a good, general template, which people which just finished a business plan usually don't have. I would recommend you to search for general guidelines about how a business plan should look like and then ask specific questions here if you have trouble getting one of the guidelines implemented.

Is there a good business plan template?
According to this question freshwater fish should not be used in Ceviche--why not?
