MTthorpe ...
I thought about this a bit more, this morning under the shower 
I think it depends a lot on what you want to shoot ... but you added the info that you might be into weddings (lot of good threads on that one on the forum).
- Are you sure you have all the lenses you need? Many photographers eyeing the 1DMKII have already satisfied their lens hunger
- Would a used 1D (MKI) also be an option for you? What about a Kodak DCS 560? The latter has 6MP, 1.3 crop and the 1v body with all its advantages, but not the FPS of the 'real thing'. They sell sometimes on eBay (1D for about US$ 2,000, DCS 560 in the US$ 1,000-1,500 range, but scarce) Might be more interesting, of course, if you want to shoot motorsports. Don't know how well the colour rendition of the DCS 560 is.
Maybe in wedding photography the 6 MP of the 10D or DRebel would be more important. I think the DRebel might be sufficient as backup camera. But then, most likely you also have a Canon film body that could serve as backup.
Best regards,
Andy