I'd either get a nice stock done for you currrent .243 or get another #1 and have it customized with a new stock and a rechambering to something different and not available as a factory chambering. Two of the same gun in the same chambering just doesn't make much sence to me.
For stocks maybe start looking at Wenig.
Actually, start here: http://groups.yahoo.com/group/ruger-1/