I think my situation is more like Neuro's - a weekend warrior who's a semi gear-head, saving up enough to go for a 1D-series body. The only difference is I took the dive with 1D4, and now Neuro will have his chance at the 1DX (of course, I don't have so much in-depth knowledge of camera workings as Neuro has

).
As a first-time 1D-user, I think the difference between the prosumer and pro model is very significant, and it takes some time to get used to (I had the 5D2 before). However, I have to say the 1D4 is a very trustworthy machine; despite the loss of the wide-end due to the 1.3x crop, I think it takes care of most situations for me.
Now, if I had a choice of 1DX and 1D4, I would have jumped at the 1DX simply because that's exactly what I wanted in a 1D-model: FF body with good FPS rate that cost way less than the 1Ds3 (I can accept a price along D3 level, but the only thing Canon has was the 1D model, so there wasn't much choice).
So to answer Neuro's question (though I'm not the kind Canon would ask for opinion ;D): Yes, I would buy a 1DX - provided I can get rid of my 1D4 at a good price.
Since I'm not a pro, I can't comment on their consideration on whether to keep or sale their equipments. For me, I would say that one pro-body is more than enough for me. While the 1D4 is a great tool to capture images, it is a real pain to carry around with all those lenses (I cannot imagine what if there's two 1D bodies *shiver*). Of course, it comes in real handy when you get caught in a drizzle but there's a great scene you don't want to miss.
At the end of the day, I guess it's a matter of your priorities. I think the best configuration (for a weekend warrior) would be a 1DX and another 5D-series body; one for raw muscles and one for portability.
Just my 2 cents.