cabs....I was travelling solo...BUT...that really should not make any difference to the price asked for 2 people (which I think you were).
The price rise I was referring to was when having customers above 2, so if there is 3 customers...that is when Clemments claims you need a larger car - which supposedly costs $50US more..
Nauga - yes, I agree that trying to make you 'upgrade 'to a larger car just because there are 3 customers (5 can fit in one of the smaller cars okay - especially if only going to the Kayan villages which aren't all that far from town) is 'pushy'...but what I, or you, think about that means little....if that is what they ask then that is what you will have to pay, IF you want to go ahead.
Motorbike option....?? - if you mean you travelling on the back of a motorbike with the guide...theoretically that should be an option...but again, similar to the situation in Kengtung now, when a guide makes a name for himself and gets plenty of business coming there way, why would they want to spend an uncomfortable day on a motorbike, when they can have customers fork out the $$ for a nice comfy air-con car...(similar even if you wanted to ride your own motorbike along with the guide on his..).
With the situation in Loikaw, and the rapidly increasing number of tourists going there, 'you' as a tourists have very little leverage when trying to reduce your costs...