Different pairs of shorts are going to feel differently stretchy. I have a pair of cheapo Performance shorts that i like because they are very stretchy and don't leave lines on my stomach (which is not quite a sixpack, or maybe it's a sixpack of jello jigglers?). But then I have a pair of Trek shorts that are much less stretchy and I like them too because I feel that they really 'hide the bulge' and they make me feel great.

I have a short torso as well, haven't tried any lowrise shorts but find that some shorts have waistbands that are more friendly to my stomach than others, so I tend to just look for those when I shop.