We do many Joomla integration, but one we've worked with extensively is the combination with Ibcos Gold. Ibcos Gold is a stock control and ERP system used extensively in the agriculture, construction and haulage industries. The Gold system can manage stock and sale of vehicles as well as many other aspects of a business related to back-office admin and sales.
As the Ibcos Gold system has an xml middleware feature, it is possible to harness this for the automated updating of an online shop or catalog. Based on this, we created a suite of tools that allow a Joomla website to be updated from the xml output of the Gold system. This keeps stock levels, descriptions, prices and image up-to date, allowing your website to always accurately display the information stored in you office-based system.
This is quite a specific service, and the integration needs to be tailored to each Ibcos Gold set-up. Please get in touch to discus your requirements.
Ibcos Gold is developed and sold by Ibcos Computers Ltd of Poole in Dorset, UK. For more information on Ibcos Gold, see http://www.ibcos.co.uk/gold-software.html
Below is a system diagram of the Ibcos Gold application.