> How would you do it without a lot of external logic?

Logic analyser ? Or is this in the field ?

Otherwise, if *some* external logic is OK, a gated 4060. For
each channel concurrently or one at a time via a demux

I'd even consider a micro, 12F maybe, for each channel, just to
get the job done. Flick the data over in a quick serial burst

More details needed re cost, weight, space, other tasks etc

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist