Check out Zadar by ...
-- cg_funk...the fact that it doesent go to negative voltages...
-- Tomes
...is not a problem at all once you have a CV 'conditioner' or mixing attenuverter/polarizer such as 321, SISM or, on a tight budget, M-120. They can scale and shift your CV where you need it. Combined with any old standard ADSR, LFO, ... , it will multiply their uses.