Let’s also not forget that at the end of the Season 4 finale, “Doomsday,” Rose stayed behind in a parallel universe with a fully human duplicate of the Tenth Doctor, but it’d be easy enough to conjure up a timey-wimey explanation for how she’s back in the main reality again.
Plot-wise, the sky’s the limit on what the Tenth Doctor, Rose and Jack could get up to in a Doctor Who movie, although it would need to be set before “The End of Time,” the two-parter that ended with the Tenth Doctor regenerating into the Eleventh Doctor, played by Matt Smith.