I guess anything can be done and the wool can be pulled over the eye of the unsuspecting.
I think a salvaged title stays with the car it's whole life even when moving from state to state but, the term "salvaged" is, if there has been an insurance claim and the vehicle has been totaled out by the insurance company for the reason that the repairs cost more than the vehicles' value(or there abouts).
If a car was flooded for example and fixed by the owner or someone else at their own cost, the title won't show salvaged. I don't know why anyone would want to incure such a high cost though! But, for a car to be taken out of state, fixed and returned to TN, I don't think that this will change the title.
The crime/penalty is very high for doing something like this. More likely than not, if the title is clean then, your in good shape. The owner of any vehicle that your looking at, should the car have been in a flood, Im sure that the owner took the insurance money and let the car go to salvege. Therefore the title will show "salvage".
During an insurance claim, once the insurance company tells the owner of the car that the car is totaled, the owner has to make a decision on wheather they want to buy back the car "cheap" or let it go and take the money offered by their insurance company and then the owner of the vehicle has to sign over the title. Either way, the title has to be signed over and a new title reissued stating such, some how, some way!