I think he was suggesting he would either get 2 x 900nexus (to use with his existing 500 mixer) or to get the RX and a single 900nexus. Both options would be just over £2k.
Without finding a great used bargain I don’t think 2 x 900nexus and a DJM 900/850 are going to be doable for £2k. Probably closer to £3k, or more if buying new.
Personally I would have a think about whether or not you really need to maintain that CD ability- I thought the same as you about CDs when I brought my old CDJ900mk1s and I ended up using the CD drives about 3 times. One of the big benefits of all of the new Pioneer units is their use of the Rekordbox system for preparing and analysing your music- and anytime you play off of a CD you lose all of this benefit.
I would either go for either:
-the pair of 900 nexus,
-the XDJ-RX on its own (there is no point paying an extra £1k just to add a CD player to it, especially when it only supports 2 channels at once),
-a pair of XDJ-1000 (a CDJ without the CD drive, plus a touch screen that is bigger than the 900Nexus, and has things like hot-cues & beat-jump etc that you don’t get on the 900 series). A pair of these would cost around £1,500 - £1,600 new, leaving you some decent budget to pick up a high-ish end DJM mixer second hand, ideally a DJM850.
I reckon a pair of XDJ-1000 new plus a used DJM850 would cost around the same as an XDJ-RX & 900nexus and would be considerably more capable setup (minus the CD capacity) and would give you a high quality 4 channel mixer at the heart of it should you wish to expand your setup later.
One thing I would say is to research all of the capabilities & features of the various decks in considerable depth before purchasing- unless you are buying the very top of the range decks (CDJ-2000nexus) Pioneer remove numerous features from the ‘lower’ models in the name of product differentiation, despite these ‘lower’ model players still costing north of £1k each…
This is further complicated in the current climate with the current top-of-the-line model (the CDJ-2000nexus) being several years old and consequently many people are remarking how the new XDJ-1000 & XDJ-RX have noticeably higher resolution displays, despite being significantly lower range models.
All things to consider, but just make sure that the model you go for does everything important that you want (invariably it won’t do everything you want unless you go for the 2000nexus because that’s how Pioneer sell them), and don’t get too hung up on CD capability these days as the main benefit of the new players is Rekordbox which isn’t compatible with CDs anyway.
Personally I would go for a pair of XDJ-1000 and either a used DJM-850 for around £2,400 total or used DJM-800 for around £2,100 total. 