Heath, Dynaco and Knight are long gone. If you really want a complete kit including encllosure transformer, etc, Velleman seems to be the only option. In this respect your question is moot as they are the only game in town.

If you are willing to take more time (perhaps a lot more time) and workout a whole variety of construction problems you can consider AKS, Elliot, Marchand, Seal Electronics or Self. Ther may be others. These range from all you get is a PCB to a PCB plus components. I don't think any include transformers and enclosure although the come with copius instruction and info.