I’m also interested in this. The biggest issue is that a lot of the proposed services in this thread are debit cards not credit cards. They don’t come with the same buyer protections from fraud and bad merchant behavior. Some do offer protection but the terms of it are a bit different.

I’m looking for a credit card with unlimited active cards that I can revoke on demand, Starling for example limits you to 5 active (Starling are great BTW). To be truly useful to me I’d want each merchant to get their own card.