Lets see, does anyone buy a single brick of LEGO?........no, you buy a LEGO set.......not a set of LEGOS or a LEGOS set, you buy.......wait for it........a LEGO set.
Scenario example. You and a friend are playing with your LEGO, your friend steals 2 bits you wanted to use to finish the Moonbase you are building, do you say
a) hey, i wanted to use those LEGO
b) hey, i wanted to use those LEGOS
c) hey, i wanted to use those LEGO bricks
d) hey, i wanted to use those bricks
e) hey, i wanted to use those bits
most people will choose d or e if they being honest so plural arguement is pointless.
The Ford/Fords example doesnt really work unless you are being verbally lazy, you dont buy Fords, you buy a Ford Fiesta, or Ford Galaxy, or Ford Escort, if u did buy multiples then you buy Ford Fiestas or if buying a mix of models then you are buying some cars. The cars are not bought so you can combine them together to make a super car, ok its possible to swap an engine from a Ford Fiesta to another Fiesta, but not to a Ford Sierra for instance. At least not without much work. Therefore Fords isnt a word in the example, however Ford's is when referring to the company itself, not the product.
However with LEGO, you buy LEGO sets, then like the cars there are different groups, Pirates, Space, Sea etc. However you obviously dont buy LEGO Spaces sets, you buy a LEGO Space set or sets. These sets can easily be combined and intermixed, therefore you can say i am buying some LEGO, or some LEGO sets, but not some LEGOS, again, its a sign of verbal laziness, bastardisation of The English Language. The Sheep example bears the case that there are exceptions to the rules of The English Language in definite form, however in their own way these exceptions become rules within themselves due to the words being nouns. Therefore LEGO should be left alone as it is, LEGO, not LEGOS.
yes, it was a boring day at work to give me time to write this nonsense...hehe