When we modify and existing motor controller design, we are starting from the base point of a proven design. Modifications to the power output stage as in this case (physical layout changes are another good example) can therefore be completed very quickly by increasing the current handling capacity of the board and changing key component specifications such as mosfets.
If you are looking for a specific motor controller then please do get in touch with us to discuss your requirements as we have an extensive database of designs, many of which are not part of the stock range but which can be adapted or modified to meet your requirements.