While I was searching various vendors for a media reactor, the first thing that became clear was the small ones (c. 100g capacity) were not in stock. I was reading my local Reef Board (WAMAS.org) and found a vendor that supplied everything you need to build one yourself, so - if you are even slightly capable of putting acrylic and PVC together and gluing it, here is a great media reactor !
AVAST Marine Works - MR5 Media Reactor Kit - Product Details
and here is mine:
AVAST Marine Works - MR5 Media Reactor Kit - Product Details
and here is mine: