Wow seriously old thread. Either way the question was never definitively answered. I have been wondering about this for the last 20 minutes after finally deciding that I'm not a fan of the way the cup holders are designed in respects to the individual size of each holder.
After searching on google and CL and LOC, I haven't found out the answer. I'm a bit hesitant to just buy the part and hope it can be done. Brand new the part is ~$140. Not my particular price range, but would look into getting a junkyard/salvage part. I know a dremel would do the job all the same but the ls430 has those little flex arms. That in conjunction with a lovely set of wood trim for the ls430 cupholders (I recently found on JPY) has me kind of set on finding out if this can be done.
Anybody know anything about the subject at hand?