Spring reverbs sounds great. I built one inside a 19" rack and though it would be cool to have one inside a stompbox aswell, but spring reverb tanks are usually way too large. But by accident I found a old mini-spring reverbtank inside an old PA-head that was going in the dumpster. So this is my true Spring Reverb Stompbox. :)
Only one problem.. when stepping on the footswitch the reverb would make a big thundring noise from the springs. But I solved that by putting the footswitch in a separate little box. The footswitch only breaks the groundconnection to a relay inside the reverb-box that handles true bypass. A balanced cable between the box and footswitch sends +9v to the led aswell. I also added the AMZ Buffer/Splitter so I could have 100% wet reverb. Here's a sound example:
Here my 19" spring reverb with a fullsize reverb. It also houses a Rebote 2.5 delay
100% wet reverb into the Rebote delay with high feedback into a lightly distorted guitaramp makes a great noise machine. Here's a soundclip with no other processing done: