Fuse box to replace the stock one

The interior wiring harness in my 68 Cuda is in real good shape but the puny 6 fuse fuseblock has rusted terminals. I could probably use a wire brush attachment on a dremel and clean it up but I'd like to add at least 4 more fuses so I'd like to just replace it. Checked at NAPA and they had some universal fuse boxes but seemed real pricey. Has anybody replaced just the fuse box with a larger one that still fits in the acreage available where the stock block sits and if so what did you use? I can solder real good so soldering in one is no problem