For the past few days, I've been working on implementing record drivers, as discussed on this wiki page:
I have created a branch here for the changes:
As of this afternoon, the first phase of the work is finished. All MARC-specific functionality has been moved into the MARC record driver and its related template files.
The next step, which I will begin tomorrow, is to create index-based alternatives to all the MARC pages so that reasonable default functionality exists even when a record driver is unavailable for an entry found in the Solr index. Some of this is already done, but there are currently a lot of placeholders that need to be filled in with more complete information.
I'd recommend waiting until phase 2 is complete before actually installing this and testing it -- I would prefer to get feedback against the finished product rather than this intermediate version. However, I figured this progress was worth announcing, since the basic architecture of the record drivers is now in place. Feel free to take a look and let me know if you have questions or comments. I'll post another announcement when the second half of the work is done.