Our shopify site will be wholesale only, selling only to retail accounts who have credentials.
While we can use a "generic password protected" site, it doesn't explain to someone who finds our site that they must contact us for the password and be registered and able to prove credentials before entering the site and gaining access to wholesale pricing.
My wish would be for a "pop-over" to have a little bit of dialogue which would explain the requirements to become a retail partner. It would also collect information; Store Name, Tax ID number, User Name, Phone, email. This information would be forwarded to our office where we would establish the users credentials and send them notice of the password to enter the site. If the user is already registered, they would simply sign-in with a password.
I wrote an App that does exactly as you describe. Collects all that info... renders it into a simple management grid where you can approve accounts etc. and also lets the user know their access password to the site.
Since it lives on a subdomain of your Shopify, it can also serve to let them directly in as long as the form validates that they submit.
Let me know if you're interested.