Note that this is a PCB/panel only - it is up to you to source appropriate components and build the module up.
PCB and panel set for a dual sample-and-hold/track-and-hold circuit using the tried and tested LF398 sample and hold amplifier - both channels are independent of each other and are configured such that 5V+ on the trigger will 'sample', with ground being 'hold'. If you want to get the classic stepped bleepy random voltages then you need a noise source too ...
This is a fairly simple build - all of the parts are readily available, although I advise shopping around for LF398s as they're relatively expensive and prices seem to vary. A lot.
The spacing of the two ICs is such that things might be a bit tight with certain DIL sockets, turned-pin types in particular - if you're feeling confident then you can just solder the ICs straight to the PCB.
As with most of my other modules, the panel is made from laser-cut 3mm perspex, suitably engraved.
You can get panel files, BOM etc. from here: https://bitbucket.org/yorkmodular/dual-samplehold-kit/src/master/