Not until recently, none of my cameras has eye-cups or another kind of eyepiece accessories on it, including those bodies that have their OEM eyepieces missing or damaged. It is because they are just relatively too expensive, pretty much like replacement lens caps! However, this changed when I discovered that some of the old Nikon eyepiece accessories are actually compatible with today’s DSLR bodies.
First of all, retangular eyepieces on all Nikon SLR/DSLR bodies (e.g. EM, FG, F-301/N2000, F70/N70, F80/N80, D40, D80, D200, etc.) basically have the same dimensions. I found this out when I tried to put an eyepiece adapter I bought for my EM onto the eyepiece of my D40. In other words, this $2CAD eyepiece adapter which allows the EM to mount round eyepiece (older 19mm ones, I will talk more about this below) attachments serves exactly the same purpose of an in-production DK-22 which costs more than 3 times the price! However, not all retanglular eyepiece accessories are interchangable among old and new bodies. For example, when I tried to put the eye-cup that came with my D40 onto the EM, it fitted only loosely plus the film door is blocked by it.
For round eyepieces on Nikon bodies, there are only two different sizes, 19mm and 22mm. All Nikon bodies that have 19mm eyepieces are older manual focus ones. They includes the Nikkormat, the FM/FE-series, FA, F, F2 and non-HP F3. All other bodies with non-rectangular eyepeices should have 22mm round eyepieces. They includes F-801/N8008(s), F90(x)/N90(s), F100, F3-HP, F4, F5, F6, D700, the D1-series, the D2-series and the D3-series. This means that an in-production DK-7 in its “modern packaging” will be exactly the same as 20+ years old DK-7 packaged for the F-801/N8008 (see top photo).
So what I am trying to say is if you are patient enough to wait and dig around in the local stores or on the Internet, you should be able to find eyepiece accessories packaged for older Nikon bodies to be used on your modern DSLR for might be half the price or even less.