These small cheep Wi-Fi modules look promising. https://www.itead.cc/smart-home/sonoff-wifi-wireless-switch.html
There is a low voltage version that can use 4- 24 volts which not only will trigger that voltage on/off but you can have it trigger 110 on/off https://www.itead.cc/smart-home/sonoff-sv.html
I picked up the standard(non low voltage model without RF) to play with adding Wi-Fi to my outdoor wood furnace.
So far it looks promising.
The fact that RF can be added to both versions opens up the possibility for this to work with X10.
In fact I even suggested X10 support be added in their forum.http://support.iteadstudio.com/support/discussions/topics/11000002347
They have suggested that ideas that get lots of votes are more apt to get implemented however my suggestion has only one other users liking this idea
If you like the X10 idea, log into their forum and vote for it!
I plan on ordering a few of the safe voltage (low voltage) model in order to experiment with some 12 volt things at my off grid place once I have the furnace mod working.
The only current draw back with these right now is they use the cloud
(X10WTI made me hate cloudy days)
Itlead has maintained a SDK is coming by end of April.
With a SDK it will be able to have them work with X10 via software