As exper said, Mutable Instruments Veils and Intellijel Linix are good, clean VCAs with mixing capabilities, which is a huge plus. Also take a look at ALM Tangle Quartet, which also mixes down four audio/CV channels, and is a really clean VCA in less HP. I agree that Shelves can be shelved for the time being. If you really think you'll need more filtering than what Korgasmatron's gonna give you, check out WMD/SSF MultiMode Filter, which packs a lot of punch in 4 HP.