ChessV was a great and ground-breaking program. It is getting a bit outdated. But recently its author, Greg Strong, returned to Chess programming. So we can look forward to a follow-up.
In the mean time there are alternative configurable multi-variant programs, mostly as WinBoard-based engines, so they can be played against each other automatically. (E.g. Fairy-Max, Sjaak II, Nebiyu). They are usually stronger than the good old ChessV. There is also a large number of WinBoard variant engines that are not configurable, but play just one variant, or a closely related group of variants (e.g. HaQiKi D for Xiangqi, Shokidoki for Shogi variants with drops, HaChu for large Shogi variants without drops).
Note that the 'great variants encyclopedia' at scribd seems to be a copy of the Wikipedia page on Chess variants, for which they then charge a fee...
ChessV a software program capable of playing over 60 Variants using a strong engine with analysis possibilities. The author preferred to allow new variants to be easily added providing they share a commonality with the existing games structures, permitting a stronger engine to be constructed.
It is a shame that it seems to be forgotten, but maybe it is time to have another look [click here] .
Zillions of Games seems to have resurrected itself after an absence and a great variants encylopedia is available on Scribd at https://www.scribd.com/doc/73339358/Chess-Variants-Collection.