We're successfully using Layout C and the white form page, and have had zero complaints about the lack of branding or the odd domain name.
(We were one of the early adopters in the linked discussion, so you can probably blame us for the lack of an iFrame -- we were getting continual failure reports from users due to the third party cookie issue. Since the change, not a single complaint.)
We were able to put our logo at the top of the "Billing Information" form, so perhaps that's helping users feel comfortable. I honestly can't recall where we did this, but it's somewhere within the twisty maze of passages that are all part of the eJunkie configuration screens.
Once a user clicks off that page, they are taken to the actual paypal https site, so I think that allays any fears -- at least for our users, it's never been reported as an issue or reason they didn't buy.
You can see our credit card integration by adding any of our products to the cart (hover over an icon and click Buy), then clicking the credit card logo: http://manytricks.com.
regards,
-rob.