Softmods and TSOP flashes are two entirely different things. Softmods work by exploiting a loophole in a font or ST.DB on every boot with the stock BIOS, while a TSOP flash is replacing the actual contents of the TSOP chip on the motherboard with a new BIOS.
Also, I doubt anything will come of the old hacked saves, am I right in thinking that the 360 is even protected against buffer overflows? Anyway, anything that has been done to the original Xbox will nearly definitely be patched on the 360, I'd guess even in the emulation, MS aren't daft. Well, aren't that daft.
One other thing I'm wondering, how do HDD-signed saves like Forza work on the 360? Does the actual HDD have a key again of the same format, or is one emulated? It might be worth a try swapping a 360-created Forza save to a different 360 as an experiment. I'd try it, except I don't even own a single 360, never mind a pair. It isn't of any importance I suppose, but it'd be a tiny bit more information on how the 360 does things at least.