Based on my own purchases E3B, AmigaKit, Jens Schoenfeld and Elbox are all still active and producing and/or updating their products and plan to release new products. I have a Mediator 4000 MK2 (it's labeled differently both on the box and circuit board, for example).
The GVP stuff is available (from the new production run). I got one of the newly produced GVP Spectrum graphic cards last year. Although I think some of that new stock is sold out now.
Similar experience to me, got a mediator 4000 through Amigakit in December, a GVP 4060 in January and today received direct from Elbox a Radeon 9200 5 volt version for the mediator...busy weekend ahead
