...how long it takes to get to that level will determine how long it takes and how much it costs I suppose. I am currently looking into ways to make my IFR hour building as beneficial as possible for this reason.
At our school we have a Frasca 142 that can be used for a very reasonable price. Also a few IRIs and an IRE on staff. The way some of our students are going about their professional training, is to get the IFR hours in the aircraft while hour-building post IR(R), and absolutely hammer the sim on all the procedures... so when they come around to training "down the road" at the ATOs with the approved sims, and are paying £200/hr, they shouldn't need to go above minimum hours training.