Actually, I started out with that, but it doesn't quite work, in the following 3 ways:

1. The implicit resolution of the option case classes doesn't seem to work, i.e. 
`padRight(testDVD, 7, Value(10d)  )` cannot find the `Impl3[DenseVector[Double], Int, OptPadMode, DenseVector[Double]]` in the UFunc object

2. Given that Ufunc already uses implicits, one can't do `padRight(testDVD, 7, 10d  )` and implicitly convert the last `10d` to `Value(10d)`

3. One cannot use named variable calls with the UFunc implicits: `padRight(testDVD, dimensions = 7, mode=Value(10d))`... not quite relevant here, but would be very convenient if I put in more options along the lines of the Numpy pad function... there is not a natural argument order for their myriad of options.

What do you think?