There are some off-brand circular saw type blades that are about 1", same as the cut off wheels, maybe a little bigger.
They might require a different mandrel than Dremel makes.
Here's why it's a good idea to stick to one brand as much as possible. If you get an off-brand mandrel with a weird sized shank it might not fit the collet right. If it's a bit too tight you could potentially damage your collet, but if it's too loose you could potentially throw your bit. If it's going fast enough, you might get into more trouble than you bargained for. Of course, you could also check to see if the manufacturer of the off-brand bit also makes a collet that fits your handpiece.
Now, this stuff is usually pretty standardized across brands, so there probably won't be too many difficulties, but I've had some weird stuff happen with off-brand stuff, so just be watchful when you experiment with something new.