I'm happy to report that Seeking Michigan is slowly adding images for more Michigan state census records dating between 1827 and 1874. Since late January only the 1845 St. Joseph county images have been available, but records for Clinton and Eaton counties are now online as well. If they add all of the census images available at the Library of Michigan here is what we can look forward to:
Branch 1854 (incomplete), 1874 (index only)
Eaton 1845 (abstract), 1854 (index only)
Houghton 1864, 1874
Kalamazoo 1837 (abstract), 1874
Oakland 1845 (abstract)
St. Clair 1845
St. Joseph 1845
Van Buren 1845
Washtenaw 1827, 1834, 1845
According to the Library of Michigan (LoM) website “abstract” means that the copy in the LoM was transcribed from the original source. The term “index only” means that the LoM has an index, but not the actual record. I find this somewhat puzzling because the images for Eaton county for both 1845 and 1854 are now online at SeekingMichigan. This begs the question whether the information from the abstract/index was copied back onto census forms prior to uploading (which seems unlikely to me) or whether the actual records were somehow acquired. Either way, the images are available and everyone will have to determine how much weight to put on the information contained therein.
Keep in mind that these are early census records and therefore don't have as much information as later ones. The 1845 records include the name of the head of household, the number of white males over 21 as well as their names. Ages for all whites in the household are indicated by check marks. There are also columns to note colored persons, indians taxed, persons deaf and dumb or insane.
The form for 1854 and 1864 provides slightly more information. It lists the name of the head of family and those over 21, the occupation of those over 21 and ages of everyone in the household (check marks). There are also columns to note the number of married/unmarried people of each sex, and to indicate blind, deaf and dumb, insane or idiotic and colored persons. The number of marriages and deaths in the preceding year are also noted so don't overlook them.