Are you engaged with a company or a single developer ? If you are giving the contract to some offshore or outsourcing/service company then I don't see any issue. You might be better off because they might have people with different skills as needed (graphics, HTML, server side, system admin, database guy etc )
I wouldn't trust a single developer as I have seen it introduces too much risk.
You can try an offshore company. I have had very good experience with offshore companies. It can keep your cost down in early stages. You might have to pay $4000 per week in US but you can pay the same $4000 for a month worth of work.