Get them from South Korea, u can buy them on ebay, they have samsung panels and some are overclock able to 144 fps, mine is running at 120 right now. Cost me only 300$ with international express shipping, that was 3 years ago. Now they cost around 200 for 400 u can get UHD 60fps.
EDIT: WOW!!! the 4k's are down to 300$ only. Damn I am thinking of getting one myself now.
Yes there is a compromise, you might, very low probability, get a few dead pixels, I and many other users got perfect monitors, in the overclock forum there is a thread about these monitors.
Don;t fall for the prechecked or pre tested models, just get the cheapest with a reputable seller who provides free returns.
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR4.TRC2.A0.H0.X2560+1440.TRS0&_nkw=2560+1440&_sacat=0
A cheap 4k one: http://www.ebay.com/itm/NEW-28-4K-UHD-UpStar-M280A1-High-Gloss-LED-Lit-Widescreen-Monitor-5ms-Response-/232073170222?hash=item3608a38d2e:g:XJYAAOSwFe5XzsBa