EVGA has announced new low-power versions of the NVIDIA GeForce GTX 950, some of which do not require any PCIe power connection to work.
"The EVGA GeForce GTX 950 is now available in special low power models, but still retains all the performance intact. In fact, several of these models do not even have a 6-Pin power connector!"
With or without power, all of these cards are full-on GTX 950's, with 768 CUDA cores and 2GB of GDDR5 memory. The primary difference will be with clock speeds, and EVGA provides a chart to illustrate which models still require PCIe power, as well as how they compare in performance.
It looks like the links to the 75W (no PCIe power required) models aren't working just yet on EVGA's site. Doubtless we will soon have active listings for pricing and availability info.