Would something like this work for Rebote switching?

[MikeH]

I want the repeats to trail off when the effect is disengaged.  R and R are resistors to prevent popping (hopefully).  And the input is grounded  when the effect is bypassed to prevent noise etc.  I'm sure I'm grossly overlooking something here; any comments?

[MikeH]

When a problem comes along... you must bump it... Bump it- into shape... bump it good!

[Auke Haarsma]

Why don't you take the boss/trail part from the Echo Base delay?

[MikeH]

I took a look at the schem; unfortunately I'm just not that good at hacking circuits. 

[earthtonesaudio]

According to your drawing, when the delay is on, you have output mixing back to the input through the top "R."  Don't know if you want that...

When it's off, the output of the buffer goes through the bottom R to ground... that might require some care to ensure there's not a level drop.

Other than that, I would make one suggestion:  mix the buffer output and the "tails" output actively, both to avoid cross-contamination and for better control over the mix.

[MikeH]

you have output mixing back to the input through the top "R."  Don't know if you want that...

I'm sure I'm grossly overlooking something here