Anyway I see some problems for using those scanners in a ROV of the OpenRov type, by now.
There is already no possitioning system onboard the ROV which accuracy could be compared with the scanner resolution.
There is no "Possition holding" system onboard, appart from lying down on the bottom.
Hence there is no accurate reference frame for the scanning procedure.
Also, from what I've learned buying marine equipment, if you have to ask for a price, you probably can't afford it.