Congrats on the new car. I picked mine up the week before christmas and havent stopped driving since
I was in a similar position to you and found the car I wanted but it didn't have iDrive it wasn't a show stopper so I still pulled the trigger and got it.
I have been doing some research over the past couple of weeks and it looks like you can retrofit idrive. As knightelf mentioned there is a company in canada bmwretrofit and another one in Europe bimmer-tech that both sell the full kits. I exchanged a few emails with bmwretrofit as they were having a special on before the end of the year (~$300 off). It sounds like it would be a fairly easy install for a DIY kind of person. However be aware it also looks like you need to get a couple of trim pieces from BMW, the piece of trim that replaces the cup holders that the iDrive controller clips in too and the piece of trim that goes around the climate control and cic computer in the center dash.
I did a bunch of searching on here and a few other forums and I couldn't find anyone that had actually documented doing the retrofit to a 1er plenty seem to have done it to e90's. My main concern was if the dash needed to be cut or if the iDrive screen would clip straight in to the storage bin hole. bmwretro fit told me that it clips straight in, in 'most' situations.
I havent pulled the trigger yet, but I am certainly thinking about it.