I'm not aware of any expressly made for lifting purposes on the softies, but on the Low model, you could certainly replace it with a standard. Honestly, if it's a serious consideration for your back (and this I can definitely commiserate on - I've got several herniated discs in my low back), you're right, the Dyna family is a MUCH better choice, aesthetics aside.
Frankly, I think the Dyna is a much better choice of platform for handling, anyway. YMMV.
Thanks frenchman! Yes, the back comfort is the major consideration and the others are byproducts. My back can't take bottoming out the suspension and I'm about 250lbs, 270lbs ATGATT and 300lbs+ packed, so that will happen often on bad suspension.