I think that what you are suggesting is to drop all the strings down by a fifth, so your guitar would be tuned (low string to high string):
A,D,G,C,E,A
If that is the case, I have never heard of that before, so can't give you any insight into what may happen, beyond the need to adjust the truss rod because of the significantly lowered tension, and beef up the strings for the same reason.
The usual tuning for a lowered tuning is the Hendrix Eb with heavier strings and with the intervals between the strings having the same relationship as regular tuning.
Open tunings are a whole different kettle of fish.
Leadbelly was well-known for his open 'C' 12-string, which is HUGE sounding.
There are many great players who use open tunings - one of my favourites is the Joni Mitchell record 'Blue'. Also check out Stephen Still's battery of old Martins tuned to a variety of weird and wonderful things, plus the usual suspects - Pierre Bensusan, Davy Graham, Bert Jansch, John Renbourn, Martin Simpson et al.
The electric sound (?) you are looking for can be obtained by a baritone guitar, which would have a scale length of (for example) 26 1/2 inches, compared to (say) 24 3/4 for a standard Les Paul.
The only place I can think of where the baritone sound is prominently displayed is on 'The Return of the Hellecasters' CD on a tune called 'The Hellecasters Theme'
It's a great sound in that context, but I wonder how long it would be before it gets old.
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