http://www.ebay.com/sch/Monitors-/80053/i.html?_fcid=168&gbr=1&_nkw=2560%20monitor&_clu=2&_sop=15

This monitors based on different variations of LG 27" IPS panel (used in Apple Cinema display) are already quite known on various forums.
Different firms are making them, plus panels and electronics are also different.

Most use DVI-D Dual, but active DP to DVI-D Dual converters exist, if you need them.

Can be good option, especially if you need 2-3 monitors.