Would it be possible to have a function that escapes the marked text (or the current field, if none marked) for specific capitalization and other escapeable characters:
Proceedings of the 19th Behavior Representation in Modeling & Simulation (BRIMS)
-->
Proceedings of the 19th {B}ehavior {R}epresentation in {M}odeling \& {S}imulation ({BRIMS})
I'd find that quite useful.
It won't be a function in BibDesk. Have a look at my applescript samples on the Wiki to do this.