That Afox card is really dangerous - I'm sure it will be bought by lots of people wrongly thinking it uses less power and can be combined with their old power supplies without PCI express power connectors. Or, people may buy them thinking they'll be able to run 3 in Crossfire using a 500-600w power supply.
Otherwise, motherboards can't really deliver 150 watts per slot - that power has to come from somewhere and it won't come from the 4-8 pin CPU connector, that power is usually only for processors (though I think those motherboards with 4 way crossfire/sli do use a part to power slots). So it has to come from the ATX connector, which has only two wires for 12V.
You can't really put more than 10-15A of power on each one and even that depends on the gauge of each wire, so we're looking at best at around 350 watts through those two wires... but that's pushing it. They connector would probably start smoking and wires would probably start to melt the insulation.
So considering the motherboard itself uses about 40 watts, imho one card may work but two cards is seriously pushing it.
I really don't see the need to remove that connector, it's not like it would mess up the "1U" height.