For an even better idea what the train will look like, take a look at http://www.cedarpoint.com/thrill/millennium/mffacts.htm . There are two renderings on that page.
Height requirement? For the 310th time, the park hasn't said yet, but the requirement for the only extant similar ride in the country, Darien Lake's "Superman: Ride of Steel" is 48", and if Intamin says that it OK, Cedar Point is likely to follow Intamin's guideline.
--Dave Althoff, Jr.