I've been in this same situation for the past few months.
Short answer: You can't get them right now
I've talked to Jensen, radial, and every other distributor and no one has them. I even talked to Jack from Nobel and he's having a hard time getting a hold of them. There is a Rode branded one on reverb in Australia right now but I haven't been able to get in contact with the seller.
What I ended up doing was just waiting until I found a JDI that was cheap enough and then I pulled the transformer out of it.
With how hard they are to find, I just wouldn't offer a Jensen transformer as an option. Cinemag, Unagi, and LBA are all great alternatives.