rusefi.com

Here are some options for making the LCD on a short cable, which would allow it to be mounted in different locations.

This is kind of costly, but it's an option for $7.60
http://www.digikey.com/product-detail/en/samtec-inc/IDSS-16-D-05.00-G/SAM9041-ND/4386575

This guy on Tindie sells these for $5
https://www.tindie.com/products/WIDGENEERING/18-1x16-cable-for-hd44780-and-compatible-lcds/?pt=full_prod_search

As well these for $8.25
http://www.mouser.com/search/ProductDetail.aspx?R=0virtualkey0virtualkey14-006-173

Of course you could also make your own, using these parts.
$2.24 ($1.12 x 2) of this insulation displacement connector http://www.digikey.com/product-detail/en/te-connectivity-amp-connectors/4-640442-5/A30950-ND/698178
You would need some wire and some time.

I'm sure that these can be found in china for low $ as well.

radio transmitter making the LCD ???
Look at this on eBay http://www.ebay.com/itm/172220738061

Am I right that altogether we need 8 wires for the LCD (including power and backlight and everything) and 3 wires for controls? (Using the same gnd as the screen?)
Which awg do I choose if I want it to be 2m extended?

Yes, at the moment 8+3 looks like an OK bare minimum.

Great!

Pretty much any AWG will work with this. I do not know about the max length though. I seem to recall the LCD is clocked slow so 2M might be OK.