Potentially redundent looping question

[Kevin Cheli-Colando <kevin@minds-eye.org>]

I'm sorry if this is a obvious question I should just check the archives 
for
but,

Are any of the current loopers (Boomerang, EDP, Lexicon, etc.) capable of
opening the loop and having it decay away incrementally (like the old 
Digitech
pedals that used a hold button on the delay)?  Is this one of the upgrades 
on
the Boomerang?

I have a DL4 and a couple of Zooms and such and they all seem kind of 
abrupt
when you want to exit the loop.

Once again, apologies if this is something that should be painfully 
obvious or
has been answered many times over.

Many thanks

Kevin CC