I always thought there is a good market for development in this area. I am suprised none of the big players never really launched a product.
regarding cutting your old twin tip.... almost guaranteed to ruin your board, if it works it will snap or de-laminate within minutes. Twin tips are generally wood core with carbon fibre composite and thin. I think snowboards are metal base cores ? and therefore easier to cut up and retain strength..... but give it a go you never know