(I apologize if this response is not very helpful, but I would like to field it anyway)
I feel your pain Christian. Steer quite clear of the NTFS.IFS beta for write. It is rather miserable.
Would you be behind petitioning for a NTFS.IFS based upon the NTFS-3G Project?
When I had Xp/eCS on one machine I would flashdrive anything from eCS to XP. I keep all my valuable data on my NTFS drive so I just read-only mount the XP drive under eCS to get my pictures/movies/music/documents, etc.
I had tried the HPFS eCS volume but I found the overall performance impact on eCS was too much.
Right now I have 3 boxes on my router and I FTP back and forth. I've tried to get Samba to work on eCS and my Xbox but eCS Samba can be spotty and the Samba client is broken in the current build of XBMC.
I have been looking for a FTP.IFS but I can't find one. There does seem to be a Netdrive plugin available (payware

) but I don't have netdrive (just EVFS) and I don't want to shell out the cash to test it.
It may be a good solution for you if you can hack together a simple storage box or find a NAS device.
Along those lines, I have a computer (my current eCS box) that I don't really want/need but I can't bring myself to throw it out because it works just fine. PM me if you want further details.