Artistic Licence Data-Lynx is a good option for multiple DMX outputs - it allows 12 DMX outputs and is fully configurable.
Data-lynx is available in custom configurations, so if you only require 8 DMX outputs, you can also 4 DMX inputs too.
Another budget option is the Etherlynx II - offering 2 x DMX inputs and 4 x DMX outputs.
Do contact me if you require a demonstration or quotation
Regards
Simon