XP-sized Cyan emitters?

I assume that you want a lot of output? The Luxeon stuff is probably the way to go. Nothing relevant is directly footprint-compatible with Cree XP-series LEDs AFAIK, but the color Cyan is available. The Luxeon Rebel Color series and the Luxeon Z series are what springs to mind. Rebels have Sinkpads available and feature a thermal pad. Luxeon Z doesn’t have a thermal pad, it’s similar to the Cree XQ-series in that respect.

Edit: adding links -

djozz - LuxeonZ, the making of a copper board, and testing - I think that djozz’s custom MCPCB failed. I didn’t read the linked thread, it’s probably mentioned. Djozz mentioned it in another thread IIRC.
rollinstone157- Luxeon Rebel LEDs - Underrated performers
Fritz t. Cat - PC Lime colored SK-73 - Fritz t. Cat’s thread has some great pics!