• Graupner MX-20. Supports a lot of channels. Allows to mix multiple receivers. Great for FPV and multiwiicopter. ppm. Expensive >400
• Futaba has 12 channel systems or more. ppm. Very expensive >500
• Hitec Aurora 9. 9 channels. Supports telemetry. ppm. 391
• Turnigy 9x. 8 channels. No ppm with included receiver. Transmiter has internal ppm. Open source firmware. Extremely cheap! ~ 50

• Using included receiver and a ppm module we can control multiwiicopter. ~ 25
• Replacing receiver with frfly system. Telemetry. Supports multiple receivers but not at the same time (http://www.frsky-rc.com/uploadfile/201009/20100930115814373.pdf). Clame 1.5Km range. (look in hobby king. http://www.rcgroups.com/forums/showthread.php?t=1408118&page=2). ~ 100
• FrSky. PPM!! 4-channel has 8 ppm channels. http://www.multiwii.com/forum/viewtopic.php?f=16&t=944
• FrSky. d8r-II with cppm: http://www.youtube.com/watch?v=_lkjfvyUGg8 http://www.rc-heli.de/board/showthread.php?t=189318 http://www.frsky-rc.com/download.asp?id=23
• FrSky. Conversion! http://www.youtube.com/watch?v=DHnV6hGH108&feature=related
• FrSky. DIY module : http://www.frsky-rc.com/ShowProducts.asp?id=85
• Replacing receiver with jeti duplex system. Supports all 16 channel with mikrokopter receiver, or 8-channels with the normal ones plus Supports multiple receivers. Not clear is the range (uses xigbee inside, maybe small range) 300-400 meters (http://forum.mikrokopter.de/topic-22404.html). A lot of telemetry data. (look in mikrokopter. http://www.mikrokopter.de/ucwiki/JetiDuplex, https://www.mikrocontroller.com/index.php?main_page=product_info&cPath=108&products_id=599, https://www.mikrocontroller.com/index.php?main_page=index&cPath=108) ~ 200
• It's possible to modify turnigy to accept ppm-in signals to add another turnigy or a FPV headtracker. (a resistor)
• LCD backlight mod is almost necessary.
• Turnigy mod, using frSky FJT. http://www.daddyhobby.com/forum/showthread.php?t=67760
• Guía español: http://www.aeromodelismovirtual.com/showthread.php?p=172718

We can use the turnigy 9x/flysky th9x to learn to fly in linux.

• Download and compile crrcsim
• Disconnect transmitter module from 9x and connect audio cable to 9x and to mic or line-in input in your PC
• Run crrcsim and configure it to use the audio signal as input device. Then calibrate device.