I want a hoverboard/ultralight helicopter.

I was browsing my favourite chinese junk site, and came across
http://www.dealextreme.com/details.dx/sku.15230

This is a 70mm diameter fan that takes 580W of power, and produces
1.1Kg of thrust, and weighs 116g.

Imagine a board around a meter round, with a large number - around 150
- of these fans around the edges, with a nutter perched on top, riding
it like a segway, with a collective control to go up and down.



Some details.

The fans are canted slightly to overcome any rotational effect. (of
course in a production craft, you'd want to source fans of opposite
rotation - but...)

Parts list:
http://www.dealextreme.com/details.dx/sku.15230 - thruster $38 - 116g
http://www.dealextreme.com/details.dx/sku.11983 speed controller - $29
- 59g
http://www.batteryjunction.com/tenergy-31132.html - $80 230g, 30Wh
18mm plywood - 1m*1m - 18Kg
Nutter - $0 - 100Kg.

Assuming that we run the fans normally at 500W, and they really
produce 1Kg, and the rest of the margins come from getting better
stuff as we're buying in volume, and not picking the first that
occurs.

Each battery can run one fan, and needs one ESC, for a total cost of
$150, a weight of 380g, and a thrust of 1Kg - leaving 600g of thrust.

For a 118Kg payload (plywood + nutter), that means 200 units to hover,
under normal conditions, not counting burst power, which will be a bit
higher.
Call it 250 units, giving a

So, we have a $30000 (assuming quantity discounts) 60Kg heliboard,
capable of free flight for 2-3 minutes.

Anyone see any major flaws?

This is of course merely a proof of concept doodle - in practice you'd
probably want to optimise fan diameter, RPM, and source the parts
sanely, I wouldn't be surprised if this might result in a third the
price or less if you were building a dozen.

Of course, in practice, you'd need details like:

Canting the fans to avoid overall torque (or source counterrotating
fans).
Redundant controllers - each doing a small group - (4?) of fans.
(this is where the large number of fans is a big plus)
Safety features - an altitude limiter to 10cm, and a promise never,
ever to press the big red button.

Does anyone see any real obstacles to this - what would the legalities
be if I was to try to sell this? I assume there'd be no chance in
hell?
(I do not have any funds to invest in this)