Re: 7 String Questions
Looks like quite a few views but no answers. Sometimes it just takes some google-fu to figure this out. Some places to start are the RG7620. It's a late 90's early 2000's model, but I haven't seen a decent price on one in awhile as anyone that has a MIJ Ibanez thinks they're "Rare" therefore expensive. The RG7400's are also MIJ, but don't have the Edge trem and can be found much cheaper.
The RGD's do have the longer scale. Some are affected by scale length and some aren't, but going up an inch changes things like where the bridge is located on the guitar so you may find it easier to stick with the 25.5" scale 7 strings. You will get more tension on the strings with the longer scale so you don't have to use really heavy strings to tune down, but drop A is not really tuning down. RGD's don't have nearly as many MIJ options and I'm not sure of the model numbers.
A newer RG752 is probably your best bet. Used in excellent condition they can be found for $1000-$1500.