And for this kind of investment, you can't just find people willing to write you checks. There are strict legal limits and constraints related to securities laws intended to prevent fraud.
So I think the best plan in your case, since you're not planning to grow fast and sell out, is to call that a loan and get it documented correctly as a loan at a high interest rate. Make it clear to your lenders that they are getting that high interest rate because you have a lot of risk, and make sure to check all the details with an experienced small-business attorney.
Most of these high-risk loans require what's call an "equity kicker," meaning that the lenders get a small piece of ownership even if you repay the loan, and a big piece if you default. And they have to be written up carefully because it's easy to violate securities laws.
Find some experts you can work with. If you have no idea, go straight to your local small business development center (SBDC) and work with one of the counselors there. Ask that person and others for recommendations of an experienced attorney. This whole area of investment is tricky and can really destroy your business if you don't do it right.
Related: Five Tips for Asking Friends and Family for Funding
Related: Should You Raise Money from Small Investors?
Tim Berry is the chairman of Eugene, Ore.-Palo Alto Software, which produces business-planning software. He founded Bplans.com and wrote The Plan-As-You-Go Business Plan, published by Entrepreneur Press. Berry is also a co-founder of HavePresence.com, a leader in a local angel-investment group and a judge of international business-plan competitions.