Your invention is very similar to the Harb Carvers. You can view these on Youtube and at the HSS website www.harbskisystems. com
Having been on the Harb Carvers I can tell you that yes, things of this nature can be very valuable tools to work on skiing technique in the off season. Keep us posted on your progress.
I know know Harb carvers. I suppose the only similarity is the purpose of simulating carving. From the design point of view my device is completely different. First of all the wheels in my ski simulator turn sideways as you edge and those in Harb carvers are fixed. Not only this but my wheels are synchronised and turn sideways in the opposite direction i.e. when the front ones turn left the rear one turn right by about the same angle.
Also, the length of my skiing device is about 1m (3.5feet) and there's not risk of falling forward or backward when you hit a bump and go a bit off balance. My wheels are also larger, currently 5" but I'm sourcing even larger 6" ones which should work better on a rougher than tarmac surface. Appreciate your comments, thanks.