EDIT: some artifact of the server migration has made it hard for me to keep up with new posts as they are added. Pretty much everything I say below--at great length!--was said more elegantly and succinctly in post #30, above. Sorry.
What you said: "I don't think I do anything special, other than EQ my rig around the other guitarists, but I guess you could say I have found a 'signature' tone over the last year."
In the best possible way, I think you answered your question right there. It sounds like you have your ears turned on and are considerate of the common goal: a good-sounding mix. If you are able to hold down your part of the mix without sonically stepping on your bandmates, and you are satisfied with how your bass sounds, well...what better qualifications could there be for an appropriate tone than that?
As an (admittedly extreme) example, if you left this outfit today and started playing with a group consisting of Rhodes electric piano, flute, mountain dulcimer and your bass, the tone you were using in the posted samples would probably not be well suited to the mix. The whole point of a signature tone gets questionable (if you are indeed the kind of player with broad enough tastes and enough versatility to make a transition like that in the first place). In that case, assuming you made the switch and found it creatively rewarding, I think you'd ideally leave it up to the listener to pick out ways in which your bass-playing personality and approach held similarities to the group you were in before. Your role, assuming you found your new situation to be creatively rewarding, would be to complement the ensemble as best you can. Leave "signature concerns" to the critics and listeners to puzzle out.
All of that is sort of academic, in my own experience, I will admit. Every time I've started playing with different people, I've had to change gear right away and have found that my playing approach has changed too, when I look back on it. The "my old amp and guitar combination sucks in this new setting" realization generally hits me right away and it's a very conscious decision...but the way my actual playing and use of whatever the new gear is shifts...that happens more gradually and I don't really have perspective on it until later.
I switched from guitar to bass, mostly, several years back and am still playing with the first band I've been in as a bass player. The sounds and playing approaches of the other guys in the band seem to dictate what I need to do to hold down the low end, and I've got a tone and approach that I'm generally happy with, aside from my wish to play better. But I'm pretty sure that if I suddenly started playing with a guitarist who didn't use distortion most of the time, my tone would have to change pretty radically for me to complement that guitarist, and for me to be happy with my role in the group.
So, in short, my advice is let your aesthetic taste and the context you play in determine the tone you use, and don't spend too much time or energy thinking about consistency of a signature tone. If the band you're with has some sort of overall shift in sound from one recording project to the next, let that dictate what your sound is, and don't worry about the word "signature" being attached to that or not.
