Useable Power output of PoE ?

I couldn;t find on the Arduino Ethernet or Arduino Yun pages a description of the useable power when using the PoE modules and wanting to connect external peripherals:

Frm what i figure, the AG9120 on the Arduino Ethernet outputs 12V@12W, so one could probably get most of that - only that i need 5V. Then the power converter on the Arduino itself converts that to 5V, but therr is no description i could find explaining what the performance of that convert is. Worst case its just converting most of the 12V to heat, leaving <=5W and therefore probably < 1A ? Or maybe the power output of thst convert is even lower, and if i tried to suck out 1W i would fry the converter and therefore the Arduino ? I’d really love to know how far i could go … without wasting a board.

On the Yun it seems you need one of Silvertels 5V PoE modules, only that Ardunio still doesn’t sem to have mae any statement about which type, and some notes seemed to indicate some Yun had problems taking on PoE anyhow ? So if the Yun would take something like the AG9205 then one could get 12W @ 5V directly from the PoE module pin and the Yun itself would take only a minor part. So in theory this would make the Yun the much better poard for add-on I/O via PoE … If the arduino folks would just give some statement over what PoE board they’d really love to call supported. Maybe they are not aying anything because something isn’t working, so none can be supported ? WIld speculation ;-))