Hiya Brad,
Found some info that might remove some of the GC-ID guesswork at:
http://ubbx.groundspeak.com/6/ubb.x?q=Y ... 030791&p=2
About 2/3 down the page "Elias" says:
This has definitely been a very interesting discussion and a lot of good points have been made on how to address this problem. Let me outline our current idea and some of the reasons we've chosen it.
The current plan is to maintain the "GC" prefix, and roll over from GCFFFF to GCG000, using some form of base-36 (I'm currently working with base-32, but this can change). If I've done my math correctly, this will give us 589,832 new cache-ids. If we ever approach anywhere near that number of caches on the site, then we'll have to completely rethink the design of the site - the GCxxxx methodology will be toward the bottom of our issue list.
As Clayjar correctly pointed out, this is a kluge. When we started Geocaching.com two years ago we had no idea how this sport was going to grow. At the time, it made sense (and was super easy) to just use hex, and as a result, we inadvertently introduced the GCFFFF problem.
I understand the desire to change the prefix to provide a visual representation of the cache type, and this clearly doesn't address that. There are a couple of reasons we don't want to do this:
1. We've found that when working with geocachers, press, park officials, etc... we can almost always ask for the "gee-see" number of the cache in question. The "GC" number has become universally recognized, and from an administrative/customer service point of view, this is really important and makes our lives much easier.
2. There's an equally interesting thread on the status of the GPX format we're working on releasing soon. GPX will become the standard for downloading cache data, and it contains a ton of additional information that isn't available in the current LOC format. There's a field in the GPX file that indicates the cache type, and using this information would make it trivial for anyone to renumber the "GC" prefix to their liking based on cache type. Because of this, we feel that this renaming is best handled client-side.
I'll be more than happy to provide my code for doing this to anyone who would like it. I will require a licensing agreement though, the complete text of it will read, "You can do anything you wish with this code so long as you don't publicly make fun of Elias for his coding skills."
For those interested, here are the characters I'm using for my base-32 function. Comments on these are welcome.
0123456789ABCDEFGHJKMNPQRSTVWXYZ