I asked the exact thing on the B&B forum yesterday. Got DH to get them at mothercare last night in motorcity. For DS we got a 2 pack of Thomas for 45AED. There are also three packs of plain white. Cotton with a terry cloth lining and plastic underneath it. Looks like regular undies.
I some in Mothercare - well if what I saw is what you are thinking of....they were like pants but had like a cloth lining and elasticated legs so I guess if there were any accidents the majority would be held within the pants rather than on the floor?? They were in packs of 2 and think it was the one in Dubai Mall but was a month or so ago.