Many LED driver IC maker.
One of them is ZETEX,for buck topology, driver IC ZXLD1350 for input range 7-30V. and output current until 400mA/3W.
They support for calculate design using excel.
visit to **broken link removed**
I think you still need at least a jumper to switch between the two different load, have not seen any led driver which is smart enough to know what kind of load is attached.
You need a switching regulator for these high power applications.
The 910.27 Device from Elmos should fit your requirements. The datasheet has application examples included. For higher current levels you could also choose 910.28 which has an external power switch.