Your post presented an interesting problem; especially as I'm not a quick bread baker at all. So, it was mostly a research problem and you should take what this for what it's worth.
The first things that struck me was that the topping you described was more of a streusel than a praline; and that no matter which pan Mom used, once the upside down gooeyness came into play, the bread was more of a cake. So I googled "upside down banana bread," "upside down banana cake pecan," and "banana bread steusel."
There were a few interesting results. One, although it wasn't much like what you're asking for looked like a keeper. So, I'll link to Brown Eyed Baker
anyway: Bananas Foster Banana Bread : Brown Eyed Baker
Best for last, right? This one is going to require substituting pecans for walnuts. It may also need adjusting baking times a bit longer, and using a little less topping, so as to suit a loaf pan. But my bet is that it's pretty close to Mom's recipes; or at least close enough to tweak it the rest of the way by memory.
The comment section was striking. The bubbling over problems may actually have been the result of adapting the recipe from an 8" loaf pan (6 cup capacity) to a cake pan (4 cups). Other than pecans for walnuts, you may need not need any other adjustments.
Stay loose on time the first time you bake it, and make double-sure to test for doneness. Okay? Anyway, from RecipeZaar
, here you go: Caramel-Walnut Upside-Down Banana Cake - 286197 - Recipezaar
Hope this helps,