I have a very nice used 1000 lb capacity kubota ballast box. Bought it new in 2007, filled it with gravel and used it maybe twice. Always stored in doors. Just taking up space in the barn. It is the larger of the 2 models made by Kubota. I paid close to $300 for it and would like $125. Don't think you could begin to build one for this amount. It's located in NE Ohio. My cell number is 330-309-2879 or shoot me a PM here. Thanks