I solved my 3x3x4 in 1:20 min once. I don't suppose that's really good especially if a 4x4x5 can be solved in just one minute more.
But sorry I don't know if there's WR on these cuboids.
I should point out that 2:20 was pretty lucky. I got to skip most of the last layer, but I did have parity. I average at around 3:30.