Hi S.,
I was in the same boat with my daughter as well and it really concerned me, especially when her pediatrician made a big deal about it. She has always been a big girl and I agree that it's hard hauling that weight around. I knew she was fine and that it was just something she didn't want to do, but I followed the MD's advice and took her to a physical therapist. The PT thought I was nuts to bring her in but had her do a few exercises anyway to build her confidence. One exercise was to help her to walk by supporting her waist/hips and not hold her hands to help her with her balance. My daughter HATED it, but she gave in a couple of times. Another thing the PT suggested was when she would climb stairs or furniture, have her change her leading foot/leg to increase muscle tone on each leg equally.
I believe that every kid has a particular strength - my son was more physically coordinated and walked earlier and my daughter was a late crawler and walker but she was an early talker(both were huge kids). She's 2 now and speaks in full sentences, is learning to count and knows some colours, things my son didn't do at that age. Every child is different and it's hard not to compare them. Just have confidence that you know your child better than anyone and if your gut feeling says she's fine, then go with it and don't worry about what anyone else thinks. I had to really work to ignore the looks and comments I'd get about my late walker. In the long run, every kid catches up and you can't tell who were the early walkers or the late talkers, etc.
On a different note, since you're a scrapbooker too, did you hear about Scrapfest coming to the Mall of America in September? I've never been but can't wait!
S.