I am a little confused about the RC F not being available to order. Mine is very much "on order" and is on its way to the UK, as I "write".
I too am very keen on having a sun roof. This was one of the factors that caused me to order a Porsche 911 last September (instead of a Cayman S). I cancelled my order 3 months later, having got fed up/annoyed about the EU's treatment of the UK at that time. Events that have occurred since then have further convinced me of the wisdom of doing this.
Instead, I ordered a Mazda MX-5 RF and a Lexus RC F. Literally, two for the price of one!
As has already been indicated by other members, and commented upon by the OP, new naturally aspirated V8s are not long for this world. In fact, Toyota has recently patented a 4 litre V8 (not sure if this is to be turbo-charged or super-charged but it will be one or the other), which seems destined to replace the 5 litre naturally aspirated power plant.
I had not really appreciated the rarity of the RC F until a little while after I had ordered it but I am sure that my neighbours will be making lots of positive comments, if their reaction to the MX-5 RF is anything to go by (still relatively uncommon). There are lots of BMWs and Audis around but few Lexus cars and even fewer RC Fs.
The dealership seems particularly excited about this car; they tell me that whenever they get one in for servicing, they all gather round to admire it - and listen to the V8, of course!