This might not be helpful, but two ideas came to mind. 1) Wandering through the local junkyard to find a car with a similar part that could fit. A steering rack bellows I needed for an Acura Vigor was no longer produced, but one from a later year Nissan Pathfinder fit quite well. 2) Can't remember what the large end diameter is, but perhaps it's close to radiator hose size. That would seal the large end. And for the "small" end, a large rubber grommet of some sort with an OD to fit the radiator hose and an ID that would fit snugly on the tie rod. The grommet might even be one of those rubber pieces off a temporary compression-expand-o freeze plug things.
That's as far as my thinking goes. Sorry I'm not more help. Interested to see what you come up with. Keep us posted.
I ran into this same problem looking for that little replacement boot when I worked on my steering rack last week.
This might not work as a solution for you if you are keeping the steering stabilizer.
But this might work for you if you're not using the steering stabilizer.
Oreilly's and Autozone carries multiple universal steering rack boots and I found one that closely matched the tie rod size and rack diameter at Oreilly's help section. The part is called speedi-boot, part # 03670.
To use, I trimmed the speedi-boot such that I'm using the end with smaller opening and made the cut at third bellow. See photo.
I installed this trimmed piece into inner tie-rod and slid the large opening over and past the groove (where you'd normally install a boot clamp for the little boot) and wrapped it over the rack bellow such that they will both be tied together with one clamp or zip tie.
Hope this makes sense.