I was once interested in the JDI Duplex but for the same reasons as you decided against it... now that it is more expensive than 2 JDI's I think it is more flexible to have two mono instead. I would love a JDV but I think they are out of production now.
EDIT actually I find I never use mini TRS connectors on DI's myself, I prefer to use a mini jack to TS or whatever adapter cable and connect that to DI's the standard way. I try to avoid mini-jacks, mostly because until recently I didn't know a good one I could solder myself and that had a large enough cable opening for something like Canare MR202-2AT 2ch cable. But now Rean do make exactly that so I've already ordered some. I have some mini-TRS to stereo TS adapters and if I do need to attach a device with a mini jack (phone, tablet or some BT receivers) I use one of those. I notice most digital consoles have few or sometimes no TRS line inputs now, at least on the input channels (they might have aux TRS inputs) so my Pro D2 is getting used that way just to play music in the breaks, which seems like a waste of a good DI but sometimes I need to.

I agree about the LK copies, let's see how long they last. There is also an Italian brand that makes them too, I can't remember who they are but the first thing I was told about them was that they aren't as good as genuine LK. They are cheaper though. EDIT I remembered, Proel.

I think my Pro D2 uses the same "Eclipse" transformers as the Stage Bug range, and is still better than many other passive DI's, even than some more expensive ones. I need a second stereo passive DI so I think I want the JDI Stereo

EDIT and PS thanks for your comparison of the new and old model JDI's. I'd heard that the old model had a "better" Jensen transformer but who knows, and other than that one guy everyone still seems to think the current JDI is one of the better passive DI's