While most people are HIGHLY suspicious of putting big dollars to work online, there are some high-rollers that have mobility issues for whom these stakes would be desired (think home-bound/wheelchair-bound).
The key is generating and maintaining trust, every hand, every day by the site operator; there isn't a single online site I'd trust with a big deposit of my dollars, but that doesn't mean that legalized poker in the US wouldn't quickly result in a very trustworthy site.
Where to start, you are talking about opening a business in a highly regulated industry so you would need a solid management background, a team of experienced lawyers, accountants etc. and to be seriously well funded. No one wants another poker “Black Friday”.