A local brewery rep recently told me they no longer fill 1/4 bbl kegs.
For most of their draft accounts (and they are a pretty big Indiana brewery), they either do not fit in the kegging system or the customer doesn't want a 1/4 bbl in place of a 1/6 bbl or a 1/2 bbl.
Now that I think about it, I don't see the 1/4 bbl very often anymore.
Exact opposite of what we have been told, that people are moving away from 1/6 to 1/4. We have gone almost exclusively with 1/4 and 1/2 and only use the 1/6 for very small specialty beers that we charge premium for.