Hi,
Congrat' with the upgrade - I took the same direction.
There are two different approches in making theese adapters.
The first one has the SD/MMC opening in the top of the CF adapter. But the CF is not deep enough so the SD/MMC is sticking 3-4 mm out of the adapter when inserted. On the other hand it makes it easy to change SD/MMC card on the fly.
Theese cards are typically CF type I cards (leaves a small gap when inserted).
The second approach has the SD/MMC opening on the side of the CF adapter. You then have to pul out the adapter for changing SD/MMC cards. On the positive side the adapter fits perfectly in the Axim (noting sticking out and it's a CF type II)
I bought one of the second one's a few weeks ago on eBay (Item # 7607739551) for $9 plus shipment). Very pleased with it - there is a picture to see it and a link in "MyPDA".

Will