SSL Orchestration on i5800 Platform?

SSLO will run even on a virtual edition (VE), so any hardware will work.

The major limitation to run multiple modules is memory.

Release notes for 15.1.0, but has been the same for while, says you can run 3 modules with 8G of RAM.

https://techdocs.f5.com/kb/en-us/products/big-ip_ltm/releasenotes/product/relnote-bigip-15-1-0.html

Any of the current hardware have at least 8G of RAM.

So, memory is not a problem to any of the current hardware for your module requirements.

For SSLO the main thing will be SSL capabilities.

You need to know your SSL requirements, then see which device will meet the requirements.

Check this link, as it provides the detailed information about how much SSL transactions each device can handle:

https://www.f5.com/pdf/products/big-ip-platforms-datasheet.pdf