Idea being that the dumb switches are used solely for local data transfer between up to X number of App servers and storage nodes. The managed switch then handles only external communications as well as any firewalling.
Oh you have dumb switches in the mix? Not going to work as Gordon has said.
Would connect bond0 to both switches still work without STP in this kind of a setup, or is this when STP comes in? Or is there a better network topology, given that I don't have the budget for awsome HP ProCurves ;) Reusing existing router/switch (DLink DFL-800) and dumb Gb switches.
You don't need HP ProCurves...unless you need good jumboframe support. You will need at least D-Link 3100 switches for what you want.