Yes Rossi made one, and I know someone who has one. I've never had a chance to shoot it though.
No problem shooting 400 gr bullets, but your velocity estimates are +p+++ 1500 fps is a more reasonable velocity. BTW the 480 is not a exactly a low pressure round with a max pressure of 48,000 psi. Yes, not as high as a 454, but much higher than the 44 mag.
