Entity API adding bundles in a seperate module

Hello Everyone,

I am working on a module for the Real Estate industry. Originally I thought I would just modify d6 modules but realized that the Entity and Fields API were incredibly diverse and the way to go. This has forced me to start from scratch. The previous modules were very resource heavy and they were an all or nothing approach.

I have written the base module that installs an entity type and the listings bundle. I now want to write support modules that add bundles to the entity. People can choose what they want and there is a lot more flexibility with a lot less resources.

My biggest challenge is that even though there is a standard protocol(RETS) the implementation varies by provider. I need the flexibility to add on a module for MLS 1 or MLS 2 that bridges the entity and the data provider. One MLS might return csv and the next uses an older standard of tsv. The submodules/connectors can be configured individually to work with the entity/bundle. If a data provider changes their setup all we have to do is change the sub-module to work with the entity.

One entity multiple bundles is the only way I can think of doing this cleanly.

Can someone spread some light on creating a bundle from a sub-module properly?

Thanks,

Will