Hey this all sounds a bit seriouis. I have the same dream as big.al and hearing that it isn't possible is very depressing.
OK, so I KNOW deep down that it isn't going to happen, but I still daydream about it. My business plan is:
Win lottery. (hmmm... sound familiar?)
Buy a villa on one of the nicer greek islands with an airfield (Naxos is my current favourite).
Base a six seater at the local airfield doing scenic flights and perhaps the odd inter-island charter for the richer visitors.
Bribe the local GCAA official with free flights for his beautiful daughters.
Make a trading loss of perhaps £20,000 per year for the next 10 years (so pay no tax

)
Retire on the remainder of my lottery winnings and learn to fly helicopters...
Does anyone who wants to go into business want to start a "Private Flying Lottery Syndicate" with me and big.al ? Guaranteed left-hand seat up front for any contributors.
Seriously though, what would one need licence wise? Would a simple CPL be enough for sightseeing flights (I'm thinking here of just making a few extra quid in my spare time with an owned aircraft - not a fully blown business like above).