Couldn't one just ask them to incorporate a company? I know this is generally better done later rather than sooner, but it is enough of a hassle that I think it would be a reasonable indicator of commitment.
Ok, I get it that the US incurs some liabilities when it accepts inmigrants, etc... that's why the startup visa makes some kind of sense...
I'd love to go to the US (heck, even visit!) but I've been deterred several time (I've been 2 inches from the US border during my stay in Canada, but I didn't want the visa hassle and expense just for a short visit - not that the Canada visa experience was much better but I have relatives there)..