That
someone is me!

Notice, poster has same handle, Muse. Yep, I really made a project out of extending the usefulness of this GPS. I should have gotten on the project sooner because as it got closer to the Dec. 31, 2014 deadline (support terminated, website down, no longer could download courses), the site would go down, sometimes for almost a week!

They were cool enough to leave the site up for a few days after the deadline and I continued to download courses. If I had gotten on the project a couple months before I could have snagged a lot more.
That info about only 1GB of a 2GB card working in the GPS is erroneous.
Some of the Callaway CSR's I talked to were more expert than the others. They explained that you could copy downloaded courses from the GPS to your computer HDs, thereby effectively extending the capacity limit of courses. So, I ultimately have more courses to choose from than will fit on a 1GB card. I can copy courses from HD to the card, whatever courses I want to be available on the GPS.
Sigh. Well, I did get the 2GB card working in it, all the courses on it are accessible. The GPS would take twice as long to boot, I think it's because it had to read some of the XML course data for all the courses into its memory before completing the boot process, and there are a lot more courses on the 2GB card. It's not a big deal as long as the unit works OK once booted. What I didn't realize at the time was that the unit wouldn't work properly on the course. I tried it one time only and it shut down on me unexpectedly. I will experiment with it further, maybe it will behave. The unit does occasionally do unexpected things, especially if it doesn't like the battery.
Looking at the 2GB card I have today I see that on the front it
does not say Sandisk and the page for the listing at Amazon shows a card that
does say Sandisk on the front. I should have complained when I got the card, I didn't notice that at the time.
On the back my card says:
MMAGR02GUECA-MB
1 YDJ255GA 144
Made in Taiwan
Thanks for the links and support. I hadn't seen that Google Groups support post, I'm bookmarking it, there may be something in it I can use. I'm fairly expert using this thing, at least in terms of most of that stuff about dealing with it after their support terminated, but I may have missed some important info.
Newegg does seem to have some cards of interest. Here's just one:
Kingston 2GB MicroSD Flash Card w/ SD Adapter Model SDC/2GB. $4.95 shipped. Well, for that I might just go for it and hope. At least it will say Kingston, I hope! I don't know that Kingston is likely to be as good (or better?) as Sandisk, but what I have doesn't have a brand name on it at all and I have to suspect it's not so hot. I could complain to Amazon, it's been more than a year, don't know if it's worth the trouble.