While there isn't much online documentation to go on, I am aware that Jean Wells recorded in and around the Philadelphia area throughout the late 60's...
I've done a bit of music scouring from the period/area and I think it could very well be Ronnie Baker (MFSB, The Trammps) playing bass on these tracks.
Comparing two songs, the following run stood out to me:
An excerpt from Jean Wells' "Keep Your Mouth Shut (And Your Eyes Open)" released in 1969: http://www.youtube.com/watch?v=z6vOVQ3-6UU&t=1m59s
An excerpt from MFSB's "TSOP (The Sound Of Philadelphia)" released in 1974, where Ronnie Baker is credited as playing bass: http://www.youtube.com/watch?v=ligIq6o0rUU&t=5m18s
I'd be interested to hear other peoples thoughts.
Also, if there are any Ronnie Baker buffs out there, can you give me some examples of his work pre disco?
Looks like I've answered my own question to some degree. An amended google search brings up a couple of pages confirming that Ron Baker (as well as Earl Harris and Norman Young) produced and made up the rhythm section on "Keep Your Mouth Shut (And Your Eyes Open)". Given that, I'd imagine they're also the team on "With My Love And What You've Got (We Could Turn This World Around)". Not 100% sure about the other ones. Let me know if you have a hunch.