Drop-Down Selection Control

I am in the process of setting up a Custom Master UI Template to be used for all of our Modlels.  We have decided to use the Drop-Down Box as our selection control.   The drop-down box automatically adjusts its width to the longest option showing in the box. I was wondering if anyone knew of a way that we could change the drop down box to be a static width? 

Any help would be appreciated.

Thanks!

Heidi