Growing Mint for Profit

I live in Indiana and am searching for another crop to grow. I presently raise beef cattle and hay on about 35 acres. I have heard that mint is a very profitable crop. I am wondering how to get started and where I could find a buyer for my crop. I have a small greenhouse and lots of experience growing all kinds of garden, herb, and flowering plants. I have searched the net for information on this subject. I have even been to the USDA site. I can't seem to find any useful information.

I can help you, of course, but need more information before I can start this process. Mints include most spices and other square-stemmed plants (Labiatae family). Indiana is well known for their peppermint and spearmint, but that is mostly done by very large firms (like AM Todd & Co).
And really, I sense you need more information to ask better questions. You might start with my book "The Potential Of Herbs As A Cash Crop," and "Getting Started" (found at www.herbfarminfo.com). Many of the mints require specialized machinery, often not available in your neck of the woods.
Selecting which mint is often dictated by available capital equipment and other regional resources. Basils, for example, might be harvested by hand. One grower developed on 4 acres, but grosses more than $1.2M from labor and processing. It was sold to Neiman Marcus as a frozen pesto. That business plan can be found under the chapter on Cottage Industries in my "The Potential Of Herbs" book.
I am also available to help you develop a sound business plan as an outside consultant. For more information on those resources, please go to my website at www.nwbotanicals.org, and select Services under OAK. Some mints can be taken like a hay crop, to include catnip and stevia, requiring only simple equipment. Spearmint will require a bean harvester.