Determining if device can vibrate - iPhone vs iPod Touch

Question

Developing an app that vibrates when a particular event occurs. I have a setting for turning the vibrate option ON or OFF.

I would like to be able to disable the display of the vibrate setting for devices like the iPod Touch that do not have vibrate capability. I know I can do this by determining the device model using:

UIDevice *thisDevice = [UIDevice currentDevice];
    modelOfDevice = [thisDevice model];

I can then disable the Vibrate option depending on the modelOfDevice.. (i.e. not display it for iPod Touch). This works - but, I think it's bad form.. for example, if future iPod Touch devices do include Vibrate functionality, this solution would break.

So, the question.. How do I check to see if a device has the capability to vibrate??

Any suggestions appreciated. Thanks in advance.