One of the firms I've worked with at OpenAdvantage is C2B2. They specialise in Java software, particularly to do with portals, and have their own open source Java portal product, iPoint. It's an interesting product, and one I think should be more widely known.
OpenAdvantage have assisted C2B2 with some marketing and feedback on their product, and I've written up their experience with open source as a case study on the OpenAdvantage website. I think it's an interesting read, as small businesses producing open source products are very much in the minority (at least in my experience - see Senokian and Clockwork Software for two other West Midlands examples). We know of plenty of companies using open source in the West Midlands, but producers are in the minority. The article goes into both the benefits and pitfalls of producing open source, and highlights issues on both the vendor and customer sides of the business.