From what you're describing, that sounds like a Corvette $$ (two MusicMan-style humbuckers, each with their own microswitch for coil splitting and series/parallel options). What you're describing as walnut could likely be bubinga, as the standard Corvette $$, like the Corvette Standard, comes / came either with an ash or bubinga body. It doesn't sound like any other Warwick, but has a large following because it has a huge range of great and usable tones, largely because of its unique pickup placement with the two humbuckers close together around the MM sweet spot.