Transform a 0-10V into 0-5V and use op-amps as buffers?
Your first circuit is fine. You could even use 100k resistors instead of 10k to save power. Note that your first op amp will need to output 0-10V, which means you won't be able to run it off of a 0-10V supply. If you don't have a rail-to-rail op amp, I'd recommend at least a +13/-3 V supply.

As Matt said, your second circuit will not work. The gain of a non-inverting amplifier cannot be less than 1. You could use a pair of inverting amplifiers, with the first one having a gain of 0.5. That would help with your output range as well, but there would be a small load on your source.