In theory you can connect up to 112 devices directly to the i2c bus using the 7-bit address standard. That limit is based on the number of unique addresses available. In practice, however, your case will probably be limited to many fewer since most specific i2c slave devices come with a limited number of i2c addresses hardwired into the device. Many times there is only one choice. So you'll need to deal with that issue somehow since you want to connect several copies of the same hardware (at least as I understand your question).
There are address translators that you could buy and incorporate. They do a shift of the address between the bus and the device, so that makes the device appear to have an different address on the bus. That introduces some complications to the design though, so you'll have to see if it's worth the trouble.
Assuming that you can get all of the devices connected, I don't see the power consumption necessarily being an issue. You might need to choose pull-up resistors on the bus to accommodate your load, but that's probably achievable. Assuming further that you are not going to put 100 IMUs right next to each other, you should also be aware that the specification does not support unlimited physical length of the bus lines. My personal experience is that with properly chosen pull-ups you can do better than the spec, but that must depend at least in part on the design of the devices that you put on the bus. There are multiple posts here about that. This one came up on quick search, but I think there are others: