A note from Dell tech
Not that I enjoy posting pessimistic news, but I think I should inform everyone that I have spent SEVERAL hours on the phone with SEVERAL Dell techies who, after checking with their supervisors or whomever (one even gave me a call back after spending the afternoon to check), have all told me that our old Inspiron 9100's are NOT compatible with the new MR9800 card. No one could say why (since the I9100's of late are obviously compatible), but this may indeed be connected to the fact of people's cancelled parts. It is definitely possible that even one small part, such as the connection port size, was changed in the design of I9100's produced AFTER the MR9800's release.
Also, since ATI is, for a fact, not able to produce a large number of these new cards (reasoning why only Dell has access to them at all for the month of August), the fact that ONLY the XPS "officially" promised a graphics card upgrade, and the fact that Dell is receiving huge orders for both brand new I9100's and XPS's with the new card, I believe that, even if our 9100's are technically compatible, Dell may be purposefully denying access to these cards for us current I9100 owners.
Until I gave Rogue's order number to a sales rep, no single rep could find me a MR9800 or M18 part. They could not even find the part number c7070 when I gave that to them. I suspect that a higher power within the Dell hierarchy may be cancelling orders while the reason (perhaps one of mine mentioned above) simply remains a secret to all those bottom level reps that we all get when we call to order what we want.
Obviously, I surely hope that our old I9100's can in fact be upgraded from a purely technical standpoint, and I would like to ask if the first person to receive this card and successfully install it in his old I9100 system would be kind enough to confirm his success story so that all the rest of us may know and rest easy. Otherwise, I am ready to just order a brand I9100 with the new card and put mine on eBay . . . would prefer that it not to come to that.