for 'lush valve sounds' you need a valve amp, it's that simple. put the cash you're gonna spend on the pedal towards a valve amp - it's the best solution in the long run.
as for the RAT pedal, don't buy a new one (they're shite). the original RAT was great, but they're using different opamps now that sound very different. how do I know this? - I've got a mate who's mad on RAT pedals and I've gutted some of his reissue pedals with the original circuit as backups for his original.
:twisted: