I made a Lulu cosplay last year, using a total of 30 belts. It looked epic.
What I did was buy thick belts of good quality. (I lucked out and there was a sale of I only paid like R15-R30 rand each). I bought 6 or 7. I used those to create a frame, making sure I had the noticiable belts in line according to Lulu's skirt. You have to cut some of the belts (the ones higher up on the skirt)
Then I bought a lot of these fabric, slightly stretchable belts (Like really really cheap! R5 each!) I painted these the colors that I needed. I also bought some pleather belts and pieces of fabric to use as belts.
Using the pieces left over and the pleather and the painted belts, I 'filled' in the skirt. The weight came from the framework but it had a nice curve shape. I sewed and glued down the belts together.
I then attached the frame to the front of the skirt. And reinforced it like four times.
It was heavy but not unmanagable and it looked great. I'm posting the photos today. I wore the outfit the whole day at the convention. The most painful part were the 6inch heels I was wearing. :P
Hope that helps.