Well, im a website designer, if you where to fund such a website i would help you create it for 0.5% ownership. I say this, because in all honesty, you are going to need several million dollars to make a site anything like youtube.
The design its self would not be too complicated, you need a domain name, some hosting (storage) and a little web design skill.
The problem is the hosting. its going to cost you about $4000 US dollars a year to run a server, and you are going to need thousands of such servers. see, the problem is video takes up a lot of storage. a normal quality 30 minute video is likely to take up 300mb to 400mb. with a server, a standard server, you are going to have about 300gb. that will let you have maybe a thousand videos. if you take in to consideration that there are now HD videos, you can see how its going to soon get very expensive.
My suggestion, would be to set up a site, that lets people embed videos that are already on youtube and other video sites. like that you dont have to pay for the hosting of the videos, just the site, however, you wont have exclusive content either. and there are already lots of sites that do this kind of thing.
at the moment, the biggest hard drive you can get is about 3TB, so, another option would be to wait 20 or 30 years, until we have 800TB hard drives, and then you can probably make something like it for a reasonable amount of money.