Opportunity Account

[chopair2008]

Is it best practice to always create the opportunity record for the end customer and relate the distributor and partner to the record in some format?

How would you handle the situation a distributor or a reseller won't tell you who the end customer is? 

[Stevemo]

Yeah, that's definitely the way to go.  

In your other scenario you should probably just link the opportunity to the vendor/resller, and either create a custom field or use the Opportunity Description field to note that the end user is unknown.