Peek-a-blocks

I have just discovered the Fisher Price product Peek-a-Blocks were discontinued. My older children absolutely loved them. I purchased lots of assorted sets with my eldest in 2003 and I used them for my next 3 as well. Once my children hit primary school I passed them on to younger niece and nephew then their mother passed them on. I am actually quite disappointed they are no longer being made because they were educational, interactive, and made of good quality for a great price. Not the current astronomical price for collectors on Amazon. Does anyone have any recommendations for a similar product?