Eurydice

No soldering would be required, just a powered riser. This is confirmed to be working. I have the same Macbook as you, and when I get my parts I will do some tests, as well as rig it to power from a DA-220. Parts list here. This should work, and I will confirm if it does. I already have a 6-pin connector to cannibalize to connect to the DA-220. (Jacobsson's post) This is assuming the powered riser only uses the +12v and Ground from the Molex (which I believe it does) However a generic power supply should do all of this without the need to mess around with wiring, just plug the molex plug into the powered riser and you're good to go. This is at the sacrifice of portability, a grave one indeed. I may have missed something vital, so if Nando could fact-check this, it would benefit us both. If this works out, it is a fairly easy cost-effective solution for TB2 eGPUs without the bulky ATX PSUs. Cards should get more power-efficient with the smaller architectures, and so fall more into the healthy range of this 220w brick's supply.

I'm going to go through with this and buy a Thunder2. I would use Jacobsson's method to mod the DA-2 to power the pcie 6 and 8 pin power connectors on my GTX 770, and figure out some other way to power the slot, to allow some overhead for the 770's power consumption (I will probably bump up to an 880 when they are released). Just to clarify for me, and others who find it difficult to extrapolate the best solution from this ever-changing meta: 1: Would the DA-2 paired with the 75ish W from the slot should provide enough power for the 770, and be future-proof enough to upgrade down the line? (highest I've seen for a 770 was 246W peak) 2: Would this setup have the same functionality as the Sonnet Echo Express Pro that Floppah used for his native OSX/W8.1 eGPU? (I'm using a late-2013 13" rMBP w/ 8/512/2.6GHz) 3: Is there anything else I should know about this? i.e. Teemo, did you have to pull any weird shenanigans to get this to work? Sorry for bothering, as I'm sure there are posts here that explain this all in detail, but there is just so much to read.