I'm not sure if it's exactly what you're looking for, but I have come up with a solution.
First create a new quiz, then add a new multiple choice question.
Default mark can be 1.00
Set it to allow multiple answers.
Now set the grading for each answer appropriately, ensuring they all add up to 100%.
e.g. 4 questions, 1st= 10%, 2nd= 20%, 3rd= 30%, 4th= 40%
You may wish to set the penalty for each incorrect try to 0%.
Now press save changes.
Next to the question (not the "Maximum Grade" field), set the "Grade" to "10".
Do this for all your questions.
The "Maximum Grade" field should be the number of questions you have multiplied by 10.
e.g. 4 questions, maximum grade = 40
Hope this helps.