"....why can't you walk out of an MCC course with a type rating?"
A number of organisations hold approval for combined type-rating/MCC courses but they tend to be specific to particular operators and are not generally marketed to 3rd parties. For example, Bombardier's CRJ 100/200, BMI Regional's ERJ 145, all of CTC's type rating courses and so on.
The original intention of the JAA was that combined training should be the norm, which is why they halved the training requirement if it was. Unfortunately, however, they reckoned without the UK training industry's knack of making a quick buck coupled with the airlines' reluctance to invest in training with the result that cheap, self-sponsored modular training, using mainly unsuitable FNPT IIs, became the norm.
Type rating training, including any combined MCC, has to be given by a high-priced TRI whereas the modular MCC course can be conducted by a much cheaper MCCI.