There are quite a few VPS services out there that offer IPv6 only.
With those if you want to make anything on the services accessible via IPv4 you need to do it via another route, such as a VPN (or even just a port forward) to/from somewhere where you have an address to spare or for websites perhaps somewhere where you run nginx as a reverse proxy. In fact some infrastructure-as-a-service companies like CloudFlair offer this as a service: your users talk to them via IPv4 or IPv6 but they always talk to you via IPv6.
Some offer IPv6 with "IPv4 NAT" which allows you to call out via IPv4 as normal and may include calling in but not on standard ports (i.e. not 80 for HTTP, 22 for SSH, and so forth).
It would have to be SNI for SSL unless they had an absolute shed load of IPv4 addresses space available, though if they are charging for the service that would increase the chance of getting a dedicated IPv4 upon which you have sole use of port 443.
With those if you want to make anything on the services accessible via IPv4 you need to do it via another route, such as a VPN (or even just a port forward) to/from somewhere where you have an address to spare or for websites perhaps somewhere where you run nginx as a reverse proxy. In fact some infrastructure-as-a-service companies like CloudFlair offer this as a service: your users talk to them via IPv4 or IPv6 but they always talk to you via IPv6.
Some offer IPv6 with "IPv4 NAT" which allows you to call out via IPv4 as normal and may include calling in but not on standard ports (i.e. not 80 for HTTP, 22 for SSH, and so forth).