The speed modding intrigues me. But I figured out a solution, more or less.
I loaded the save before I abandoned, and had every available dwarf dump everything that wasn't nailed down. (except for metal bars)
Atom smashed everything. The dwarves nearly died of thirst doing the hauling, but I never claimed to be a benevolent overseer.
On reclaim I have a fort with near pristine architecture, with only workshops, beds/tables/chairs, and constructs still standing (and the metal bars I didn't smash is scattered in places) I only have a mere 200~ bars of metal to reclaim now and some seeds that didn't get dumped. Clean and easy.
@funburns
I knew about the mass reclaim/dump thing, but for this job i went to my stocks screen and designated the bins and barrels containing the stuff to be dumped. This lessens the items needing to be hauled from several thousand to a few hundred. If you do the mass dump over a container, the dwarves will individually dump everything in the container =X. Using the stocks screen for mass reclaim is also easier since I don't even have to select an area, everything is conveniently listed..
I like keeping the items i created with my failed fort, but it usually takes me an entire year or 2 just to reclaim everything back into stockpiles. The main reason I reclaim is for the architecture anyways.