Mounting root read-only

Does anybody have any experience with making the root partition read-only? I appreciate that there would be some issues, e.g. with package maintenance, but I cannot see any problems in principle. The reason I am asking is two-fold. (a) It would obviously increase security and (b) I am toying with the idea of converting all of my internal storage (two physical drives) to a logical volume, and running the OS off a flashstick, where RO mode would clearly be a good idea.
Has anybody tried any of the above on Mageia (or indeed on Mandriva up to 2010.2? Any advice?
Has anybody tried any of the above on Mageia (or indeed on Mandriva up to 2010.2? Any advice?