Firstly, I've solved my problem (to the required extent). I will be using a facility of our main product to encrypt the script, then when it needs to be run, decrypt it and pipe it directly through to a perl instance. Some might contend (with good cause) that there is a problem with our main product's automated encryption black box (think: `strings mainproduct` for a start) but that issue is... well... not my problem (you need to know where to stop, sometimes!) This solution is an adequate amount of obscurity for our purpose.

Secondly, in reply to this and this, I think you make a good point. I should have asked my question differently and not expected to find a solution already out there that I could just take. Sorry to offend! My mistake :)