As an alternative (but the usual safety precautions apply - working with mains voltage, etc...) you could consider a bridge rectifier and some electrolytic capacitors, thus powering the LED power supplies with DC.
The "common" dimmerable AC-DC power supplies usually have no issue with being powered with DC, and the "dimmable" part should still work by sensing the "average" input voltage.
There are some chips which don't work this way, for example the LM3450 (I've used it and I can say it's not great) that looks for the mains voltage waveform itself with a comparator, searching for on and off levels, and it won't work with DC input (it won't dim).