TF10 lacks bass? I've never considered it so

.
SE535 has a flat bass, which is good in extension and quality, but the quantity is definitely lacking. I even doubt SM64 would have enough to satisfy your bass needs. I don't know about W4. In general, dynamics are better at the bass end of the spectrum compared to BAs irrespective of the number of bass drivers.
EX-1000 has the best combination of bass quality and quantity I have heard so far. It has a wide sound stage and comes with a detachable cable. I've not had issues with sibilance or treble hotness, though some people do. EX-600 could be considered as well. The only worry is if you are after big quantity, it may fall short on that front for you.
FX700 is a great fit in terms of signature and as abhi_jollyguy mentioned, an upgrade to TF10's V-shaped signature. But, it has a few complications with usage, none of which bothers me. Firstly, it has a very short cable, which is fine when using with Clip+ pinned to the shirt, but not long enough otherwise. You would have to use the extender cable that comes with it rest of the time. When using with the short cable, at times, it has got yanked accidentally, but nothing has happened to the IEM so far. Secondly, it's isolation is not good. It's not very leaky and should provide good enough isolation when used in quieter surroundings, but I have not bothered to use it outside.
Faheem's suggestion of IE8 (more bass, but slightly veiled mids, great sound stage) makes more sense if you want it all. It has the detachable cable you need as well. IE80 is similar, but slightly different. I have heard neither and hence cannot comment on how they exactly differ from TF10.
I'd try either IE8 or FX700.