Multi-tenant application on CloudBees with multiple SSL certificates (SNI)

Multi-tenant application on CloudBees with multiple SSL certificates (SNI)

I'm building a multi-tenant application using the Play framework and
hosting it with CloudBees. A key feature the site is the ability to
purchase SSL certificates on behalf of our customers during the sign-up
process.
On sign-up, the user provides us with their custom domain name (ie,
customer.com)
We create the client account and associate customer.com with their client ID
We purchase the SSL certificate for our client and automatically configure
it on our server
The client should only have to worry about pointing their domain name to
the right IP address, not purchasing their own SSL certificate.
What we need to support at run-time:
Resolve http://customer.com or http://www.customer.com for a typical request
Resolve http://customer.ourdomain.com if the client does not have a custom
domain
Resolve https://customer.com/payment, https://www.customer.com/payment, or
https://customer.ourdomain.com/payment during the billing process for our
client's end-users depending on their domain setup (subdomain or custom
domain)
I'm trying to figure out if it's possible to use CloudBees out-of-the-box
with our SSL needs. We're assuming that SNI will suit our requirements,
but I'm struggling to determine the optimal configuration considering that
we may need to support hundreds or thousands of SSL certificates on a
single IP.
My question is:
What options do we have for supporting so many SSL certificates? Should
continue exploring CloudBees with SNI and AWS Elastic Load Balancing or am
I way off base? (ELB only supports 10 certificates out-of-the-box.) The
ideal process will be completely automated for our client during sign-up.
Any advice is appreciated.