Wow, that sucks. Well, hopefully you can use this scenario to help change their minds. Seems to me like an excellent business case for the upgrade.

You could go grab the developer edition and load it using their data in a partitioned table. That would make an excellent demonstration that would potentially open a few eyes.

The cost for maintaining code with dynamic SQL and the cost of poor query plan execution in terms of waits seems like it would be much higher if you calculate the time spent by developers to code around the issue, dba time spent tuning queries and managing additional tables (index maintenance, stats, storage, etc), as well as time spent by the users waiting on poor query plans.

Anyhow, good luck! I sure hope you can find the answer!