What about wrtnode?

It seems a great and cheap card for working together with espruino http://wrtnode.com

As it's Linux, it should 'just work' if you download the (code from GitHub)[https://github.com/espruino/Espruino].

If there are specific GPIO mappings for the pins, feel free to make another board description file and issue a pull request though...

I mean an espruino board working with an wrtnode board like if the wrtnode is a module for the espruino board.

Take a look at the Carambola 2 from http://8devices.com.

Oh right - yes, that could work nicely. If you're happy controlling the Espruino board from the wrtnode itself then you could use the examples at http://www.espruino.com/Interfacing

It'd be interesting to do something that actually made the Linux board a 'slave' to Espruino though!

Yes, that was also my thought!
I've ordered:
WRTnode - A Mini OpenWRT Dev Board DFR0328 $25.00

I ordered two of them. Quick shipping to the US also. Im trying to figure out how to compile nodejs for wrtnode, but will most likely stick to python.

My thought was to use the Espruino to get sensor data and send it to the wrtnode. The wrtnode will take care of WiFi communication, encryption and the webserver.

@d0773d if you have trouble compiling NodeJS (which you may as the board isn't ARM-based) you can easily compile Espruino to handle the webserver - although as with on embedded, there isn't HTTPS.