[I'll apologize for the length in advance...

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The problem with any rebuilt tranny is that the majority of the old 'hard parts' (planetary gears, sprockets, clutch assemblies, drums, differential, etc.) are reused as long as they are within spec., including some acceptable wear.
While a rebuild includes all new 'soft parts' (gaskets, seals, rings, friction clutches, steels, etc.), those soft parts are likely to wear/fail faster with worn hard parts.
In addition, most shops will only replace known bad shift solenoids, servos, pistons, accumulator springs, etc. Some shops will specify all new on some or all of these parts, but expect to pay a premium. (One of these parts could in fact be causing your no OD problem.)
For your next rebuild, the TransGo kit comes highly recommended. The enhanced lubrication alone is worth the extra expense, and you will also gain faster, firmer shifts which will prolong the life of the tranny. It generally adds $100-$150 parts/labor to the cost of the rebuild.
I would definitely recommend adding an external ATX cooler. They are relatively cheap ($40-$80 depending on the make/model), and really help keep the fluid temp down. I'd also recommend starting out with a synthetic ATF (like Redline) right off the bat.
Presuming the shop who did your last rebuild followed all of the Ford TSB's and upgrades, you should have essentially the same tranny as a 94/95.
I'm sure someone will suggest you talk to Doug Lewis at FPS in Georgia about one of his rebuilt trannys. They are commonly referred to as 'Bullet-Proof'. Seeing that you're a student and probably don't care to spend $2200 on your tranny, I would at the very least recommend avoiding the chain tranny shops (specifically aamco), and try to find someone with some specific experience with the SHO tranny. (BTW, seeing that you're in ME, the only guy I'm familiar with that you could consider 'close' is in Milton, MA (just outside of Boston). He charges $1400+hard parts for a rebuild with the TransGo and including all labor to remove/reinstall the tranny. Email me if you want his contact info.)
If cheapest/fastest solution is what you need, you could always try to find a recycled tranny at a junkyard (as long as they will give you some type of warranty), which would probably run in the $500-$700 range, plus labor, etc.
To close, I'd recommend at the very least bringing the tranny to a local, respected shop with some Taurus experience (not necessarily SHO - the troubleshooting steps are the same) to give you a 'free' diagnostic. It might even be worth the 1-2 hours labor to bring it to a Ford dealer so they can run the full external tests. In either case, it might identify a problem that doesn't require a rebuild. Of course it could also confirm your suspiscions. One guarantee though: Bring it to AAMCO, and they'll tell you it needs to be rebuilt - even if it doesn't!
Good luck, and let us know how things work out!