F5 has a CR noting the request to be able to run BIG-IP software in a vmware-like instance. I think something like this would allow users to test iRules without having to use production BIG-IP hardware. It should also allow you to test ASM security policies and other L7 configurations.
The CR is CR81856. It doesn't sound like it's likely to be released to the public, but we can at least let F5 know it would be a valuable feature. If you think this would help you, open a case via https://websupport.f5.com and ask to have your case attached to CR81856.
Thanks,
Aaron