Of Ibanez's current fretless basses, the only ones I haven't tried (yet) are the SRD90xF, EHB1005F and the SDGB1.
(I'm using lowercase x instead of a number since the model number changes with string count.)
Setting aside what your budget is for the moment, I'd say that each of their fretlesses are very different, both in feel and sound, so instead of picking the most expensive one you can afford you should aim towards the one that best suits the sound and the feel you want. The cheapest one (SR37xEF) is a standard Soundgear without frets. It's actually your best option if you want a conventional-sounding modern bass.
The more expensive ones are all idiosyncratic in slightly different ways. The SR50xF, SRF70x and SRD90xF are all designed in different ways to cop a more upright bass-ish tone. The SR50xF and SRD90xF are both semi-hollow, the SR50xF doesn't even have pickups, only a piezo bridge. The SRF70x is solid-body but still manages a very woody tone. The SRF70x and SRD90xF both have ultra-extended fingerboards (30 stops) to mimic the range of an upright, both have a combination of piezo and magnetic pickups which doesn't quite provide the tonal range you might expect but are still pretty flexible within the scope of what they can do.
I know the least about the SDGB1 and EHB1005F -- the first is basically a fretless BTB and aside from the color and lack of frets it doesn't seem to add any unique features that you can't get in fretted BTB basses; the second is a fretless version of the EHB1000, and I haven't had the chance to try anything in the EHB series yet (except one 6-string multiscale, it was a little too far out of what I'm interested in for me to have any strong opinions about). Both of them are only available in 5-string, so if you want 4 or 6 versions you're out of luck.
The SR50xF and SRF70x are both built to address upright tone in different ways -- the SRF70x is more flexible (it's got pickups) but is still not going to have the sort of sustain and upper-mids punch you'd be able to get with the SR37xEF, at least not without some EQ and fiddling with compression/limiting effects.
In many ways the SR37xEF might be the most versatile of the bunch -- if you want to play rock and roll on a fretless bass, that might be your best choice. I'd try that one first if I want to sound like Jaco or Pino or Kumalo or etc. Don't assume cheaper means worse, it's cheap because of economy of scale -- it can be built on the same assembly lines as the majority of Soundgears they make by the tens of thousands. This also means it's the easiest to mod if you want to change the pickups or electronics. The other Soundgear fretlesses each have unique bodies and have to be made in considerably smaller quantities.