A set of rack handles may be scored on *that* auction site every once in a great while. Have to be very diligent in checking daily - or very nearly so - to find and have a chance of snagging them if they do come across the radar.
I've never seen a set of rack ears for a CA-F1 for sale on their own, but the pre itself is an exceedingly rare piece from my watching various forums where vintage gear is traded and sold for over 20 years now. I'd think those ears could be machined (if you have connections) without a terrible effort, unlike the big rack handles.
I have a BA-F1, and when I first got it it lacked rack handles. I (foolishly) thought it was the same size, 4U, as an AU-919, which I also own two of. No dice. Took two years and change to find a pair of handles for it. Actually came from a SC-5330 that had been parted (not my doing, and don't know why the previous owner of said deck chopped it, but oh well) so I struck while the iron was hot.
Anyway, it is easy in this hobby to get carried away badly as there is so much killer kit to be had. I most certainly have, and am now at a point where I'm considering thinning the collection a bit. But, deciding what to get rid of is much more difficult than choosing what to add.
I have duplicates (in some cases multiples) of my most coveted gear. Far more than could ever be needed, but bristle at the thought of not having backups for the "most essential" stuff. Admittedly an irrational attachment to some of my gear, but so be it.