AC, I think you may be missing a point (either that, or I am!)
The whole point of having a domain name (a very good reason for it anyway) is that you can switch providers without your web presence or email address changing.

Your ISP should be a "registration agent" on your behalf, but it should not be the "registrant" - that's YOU!

Re "transparent" forwarding: with a properly hosted domain nothing is forwarded. The IP address associated with your domain name is the IP address of your ISP's actual hosting computer: it doesn't get redirected or forwarded anywhere else.

There are forwarding/redirecting services like Clicknames, which I've used for quick short-term setups, but they have disadvantages as you describe, depending on how they do the redirecting either the pages don't display your domain name, or you can't use a URL that locates a specific page in your site.

The same applies to email forwarding or redirecting: it works well enough but it has some limitations. You really want your email (i.e. mailbox) hosted by the ISP that holds the primary DNS for your domain.

('scuse the dirty language)

Anahata