I talked to my brother last night and he said the trickiest part is getting the UL certification. For something like a lamp, he felt it would be pretty easy and straight forward,
However, he did tell me that many manufacturers may already have an "in house" line where they will have a few options in design, color choices, etc. He told me this could be done at a fraction of the cost if you find someone who would be able to integrate your LED system into an existing light that they will sell dirt cheap, especially if they already deal with LED's powerful enough for your goals.
Sorry, not trying to get too into your business but my brother has been doing this for 15+ years, starting with projects similar to this, travels to manufacturers both in the US and China consistently, etc. It sounds like if you can find a lamp close enough, you may be able to skip the whole development phase, have a super simple prototyping stage and if you are happy, jump straight into manufacturing. That will save you most of the cost.