UPDATE:
I just called Pearce and spoke to them about the pinky extension for the XDM. I was told that they are in the final testing processes to verify the new products fit, finish and durability and that if all continues to go well they should be in full production as of March 28th.
She said to keep an eye on the website for availability or just try giving them a call back on the 28th or 29th to see what the status is but hopefully within the next month we should see them showing up.
I may go ahead and pick up another 1 or 2 of the XD ones to Dremel fit on the XDM magazines temporarily because I really like the feel with the extension.
Just an FYI for those of you who might be interested.
P.S. - If you have purchased one of the XDM compacts, don't be affraid to modify the XD extension. It's really easy. All you need is the sanding drum on the dremel and just go around the inside of the lip to make it a little wider and it will slide onto the XDM with no problem. There is a how to on XD Talk or something like that that I used.