For anyone interested ....
Working on this today I realised that there were some (ahem) problems
with the patch I posted, so I've fixed those and finished off the
patcher so that I can assemble a number of individual aiff files into
a single buffer.
The samples are first assembled into a buffer which is set to be
larger than I'll need (default 20 seconds, but it can of course be
The buffer that was used for loading the individual samples is then
sized to fit the total length of the new sample and the combined
sample copied to that buffer for saving (the [write] command isn't in
the patch yet).
The next thing to do is to add a coll to keep the start/end points of
the various segments in the new file, and save that along with the
new sample. (I already have that; it's just not in this patch yet).
Here it is ..