Considering that pretty much full blow GTX 1060, 1070 and 1080 are being placed in laptops. Why don't one of these manufacturers make a low profile, half length, single slot model to stand out? These cards could go into one of many small form factor PCs out there. The 1060 could definitely be made to fit one.
eBay is loaded with 2nd generation and later Core i5 SFF PCs for less than $150. Fully functional ones with a valid Windows license. One of those plus 8GB RAM, 120GB SSD, 1TB HD and a GTX 1060 would make for a killer sub $500 gaming PC.
If a very slightly tuned down GTX 1060 can fit in a 0.87" laptop and run with a 180W AC adapter. It could easily run in such a form factor with the standard PSU most of those SFF PCs come with. A 1070 woul need dual slot for the cooling but should still be possible in low profile with a better PSU than standard.