This fellow[0] designed a DDR2 interface, but I don't think he ever reported back whether or not it worked. Apparently he did it by hand in Eagle!

To address your point about tools, I think you're right about the value aspect -- good tools cost money. But then again, does the average hobbyist need those kinds of tools? How much demand is there for, say, a 100 MHz open 'scope that costs a bit more than a Rigol? Ham enthusiasts would probably rather trade around old HP/Tek equipment.

I do agree in principle that there should be something like the Global Village Construction Set, for electronics. But it would be a monumental undertaking.

[0]: http://danstrother.com/2011/01/16/spartan-6-bga-test-board/