I'm sure someone has posted this before, but a quick search didn't reveal anything. We're currently going through our SaleFaith systems and gradually replacing the old graphics with new buttons using the button tool and standard icons.
We were pleased to see that if you use 'Insert Merge Field' or 'Insert Variable' on a layout, copy either of these and paste them into the text field in 'Button Setup' the data will display in browse mode. The global variable needed a window refresh after evaluating, but this opens up all sorts of options, such as multi-lingual or conditional button text.
We've only been playing with this and have no idea on the overheads, but just in case I was the only person who didn't know this.....