I found this thread on a google search to find out if the new minisd 4gb cards will work on the xv6700 / ppc6700. This thread helped me, so I'm posting here with a definitive answer.

The 4gb mini sd card WILL work on the xv6700. I researched the bigger minisd cards and found that there are traditional minisd cards and MiniSD HC, which is high capacity. The confusing part about that is that all the 4gb MiniSD were advertised as "high speed" and not HC (high capacity).

Finally, my experience and how you can easily make a 4gb MiniSD card work in your 6700:

Based on google searches, I bought my 4GB MiniSD card from the user on ebay "grassroots-computers" The 4GB card was listed as "High Speed" not high capacity, so to this day I'm still not sure if the card I have is officially considered HC or not. Anyway, the card came quickly from that seller and when I put it in my phone, it didn't realize it had a card in it, so I quickly concluded that it wasn't formatted, or if formatted, not in the right file format. The card from that seller on ebay came with a free SD adapter and I lucked out because I just today realized I have a built in card reader in my laptop. I put the card in the SD adapter and put it in the card reader. The laptop with windows xp found the card and gave me the option of formatting it only in FAT32. I formatted the card as FAT32 and put it back in the phone. It instantly saw it and was able to use it.

Summary:
- The 4 GB MiniSD cards work in the XV6700 / PPC6700.
- They seem to come unformatted and the 6700/Windows Mobile doesn't have a format option so you'll need to have or borrow an SD card reader to format it. Windows XP will format the card fine.
- FAT32 works fine for Windows Mobile & the phone.
- The ebay seller "grassroots-computers" sells the 4 gig cards that will work in the 6700.

Hope this was helpful. This is the information I was looking for when I was trying to buy a 4 gb card for my 6700.