DSLR Magazine thinks so.

As published in our of our April 23, Canon shall, before the end of the year 2009, two new high-end professional models.

They go on to say that one of the models will maintain the smaller-than-full-frame sensor (i.e., the 1D Mark IV) and the 1Ds Mark III successor will be the expected evolution of its predecessor.  With the new 1Ds, Canon aiming stronger toward the medium format audience, which will entail even more megapixels.  Finally, the author points out a successor/alternative to the G10 will surface, around 9-megapxels though, with lower noise than the G10.

[DSLR Magazine via Google Translate via Canon Rumors]