George, I live not that far from Brisbane, well several hours drive and I love your idea of a one pickup up RG. In fact I have actually made 2 bodies exactly like you are talking about already. I have had them for about 5 months now and am just waiting to get enough cash to get an old RG from E(vil) Bay. I already have a left handed RG with a busted (repaired) neck that I made a H-S-H replacement body for out of Mahogany so those parts are used already.
I made my new RG bodies out of local silky oak. I found a huge log that the council left lying around and milled it on a home made chainsaw mill. I now have about another 10 or so 2" thick boards about 600mm long. You are lucky enough to come from Brisbane where silky oak is abundent, not only that, it is the best stuff around. Check out Jacksons and others custom shops from a few years ago and you see that they offered Lacewood as a high priced wood option. Thats just your local silky oak. Of course it is the primo quality stuff, not just stuff left laying around. It is really resonant and easy to work with. If it is quarter sawn the grain looks unreal. I think Carvin offer it, check out their site.
As for keeping your RG as is I think that is wise. If you ever want to sell it no-one will give you a good price for a modified Ibanez. Keep it stock, get some silky oak and have a go at building a body. The tutorials on this site are awesome and even though I am only new here this is by far the best site I have ever found for people being genuine, honest and willing to help people out. There is a great culture here.