Is there a dual customer system module?

I know of the dual wholesaler pricing system which is currently not quite working for 3.5 but what would be useful is a dual customer database. Where a reseller of your products could login and see a different setup not just prices and it would put them into a different part of the database because they are resellers not customers.

Also I am getting to the point where I want to start writing my own modules. I am entry level at sql and code in general. What I would like to know of is any good resources to learn how to create code that will add information to my sql database, like I want to create a custom form for people that resell my products so instead of saying bart Johnson order 50 products it would be under Bart Johnson order 4 nuts for Amy Anderson 31 bolts for john Hudson, stuff like that. So what I don't know is how the info that is gathered from the form is submitted to sql. So if anyone knows of any good websites I could look at for how to on that subject I would appreciate it, then I could start contributing modules instead of asking.

Thanks

Brad