All the ones I found are for 450 and bigger... I haven't seen a 250-size 3, 4, or 5 blade head.
I also tried to find a video of a 250 with that 500D fuselage and 5-blade head but had no success.
I think one of those little 250s with a 5 blade head is at LEAST as cool as a quarter scale turbine heli!!!