May be interesting for somebody. Because I'm absolutely not satisfied with 705's recording quality, and the chance that Icom will add IF recording is very low, I decided to make my own one based on a Raspberry Pi. 12KHz bandwidth can be recorded, and frequency will automatically get from a transceiver. It's almost ready
I will publish it as open-source when done. For Raspberry Pi without LCD, control can be done via the smartphone.