No problem. The Tourist visa is B-1/B-2 I enter with B-1 that is for Business, I state clearly that my visit is for Business, and when they ask me in customs I always say the truth, that I have a SW dev company and I'm visiting clients and looking for more. Never had a problem with that.
I think that if you get too complicated with your stories that's when you can get into troubles in customs.
AFAIK, all US visa grants are at the discretion of the officer reviewing your case. Anything that strengthens your case in their eyes can only help. However, I doubt they'll stamp visas where the criteria aren't met (which, according to the OP, he did, so that sucks).
Yes, that's what they told me, you must meet certain requirements and also the officer has to be convinced that your visa will bring something good to the US.
So it's the requirements + strong proof that you will create jobs in the US or your are a great scientist, artist, etc... or you have a lot of money to invest.
However as you say, if you are looking for funding then it might be a problem, they don't say it but you can perceive it.
I'm wondering if getting the investor money helps to get your visa.
Does anyone know cases like that?