I've never seen either of those planes before, interesting!
So, to sum up the responses I've seen so far, with the original question being:
'I appreciate you wouldn't be able to get a type rating as such after 45 hours, but in theory if time isn't a massive concern and pretending cost isn't either, after 70 hours, could you theoretically walk away with a PPL and MEP type rating, having never or only briefly flown SEP's?'
It seems that it is possible, but the consensus is that it would be unadvisable to do. However once SEP rated, there seems to be a greater divide between singles and twins.
I have to say, as a neutral (having only logged 3 SEP hours), I am really struggling to see why (cost permitting), once considered a competent enough pilot to possess a PPL, why you would not want to move up to a twin for safety reasons (obviously whilst receiving the appripriate training).
Based on the points listed, it seems from a technological point of view to be safer to fly a twin, with the main concern, seemingly pilot error, but presumably with proper training this risk should be diminished?