Dear Guy,
Right now we not have plan for integrate php to views layouts.
About your problem, you can use nested shortcodes.
[product id="[mycustomshortcode var="value"]"]
And in function for customshortcode you can generate list of ids.
Note: don't forget add shortocdes to list of allowed shortocdes in Views settings.
Please let me know if you are satisfied with my answer and if I can help you with any other questions you might have.
Regards,
Gen.
