I have the long travel thudbuster in a telescopic seatpost to get it to fit my birdie and mezzos. I love it.
Got it for about 120£ on ebay after postage about the same as the pivot. Cant see any of the pivots for any less than the TB on ebay at moment but will look out for them in future.
Most of the family make a beeline for the birdie with TB on family rides.