I believe that Amanda is a tough gal but I don't think that she is tough enough to take Jessica. Despite the pictures included in this thread, she remains in superb condition. Having completed a 6 day climb of Mount Kilimanjara, the highest mountain in Africa, during January 2010, she continues to be a gym rat. She works out two hour/day and ran in and finished this year's NYC marathon.
I believe that it would be an incredible fight when these two tom-boys meet and fight. Amanda will not be tamed easy and will cause Jessica a lot of frustration and considerable battle damage. Both women would have very good punching power and, on the assumption that they would agree not to punch each other in the face, it would be a long, brutal and bruising battle.
I believe that Jessica would eke out a difficult win and submit Amanda with a spread-eagled grapevine after a long battle where she spreads Amanda centimeter by centimeter until Amanda's groin muscles are stretched to their limits and Amanda very reluctantly screams her submission.
The battle was so intense that Jessica just lay on top of Amanda for a full minute after she accepted her submission and then marshalled enough strength to stuggle to her feet and hold Amanda's bra high in victory.