How difficult is it to modify this device for FPV?

[kaos]

http://www.ebay.com/itm/1080P-2-5-LCD-F ... 256e96e178

this is the idea:
remove the rotatable lens mechanism and replace the connection with appropriate A/V/power jack on the body. the remaining body can be hooked to FPV Rx and record the FPV fly through the jack and monitor for the FPV fly (for your buddy to look at the monitor, the pilot will be using goggles). At the same time use the lens as the FPV camera. After use, plug the lens back (already has replace the jack for A/V/power counter part on the body and use it as it was intended for.

This would be a cheap way to get both DVR for recording FPV and a 120 degree wide angle lens as FPV camera. At the same time you can use it as it was intended to or for casual family fun recording.

[Kilrah]

No chance.
It's not just an A/V/power connection between the sensor and body, it's a ~40pin flat cable carrying high frequency digital signals.

You could use it, but you'll have to put the entire unit onboard and connect the body's AV output to the video transmitter.

[kaos]

Hm, there is no 40 pin connnector to reconnect that flat cable? I can sacrifice the rotary-ability after reconnection.
Possible to convert the 40 Pin cable/ signal to plug into the FPV Tx?

[Kilrah]

Hm, there is no 40 pin connnector to reconnect that flat cable?

Well, of course you can find the matching connector, but it's not very useful as

Possible to convert the 40 Pin cable/ signal to plug into the FPV Tx?

Yes, that's exactly what the mainboard does

[kaos]

did not know the nerds around here still have things 'can't do' .