Minor update to the Retina MacBook Pro expected this week.
Sharp Bringing OS X-Compatibility to New 32" 4K Touchscreen Monitor
The display, which is aimed at retail/commercial applications (PDF), sports a 3840x2160 IGZO LCD panel and includes a capacitative touch interface and pen support. Sharp demonstrated the display running off an Apple notebook at the CEATEC Japan trade show earlier this month.
Sharp demonstrated the panel at CES earlier this year, though it wasn't running OS X at the time: