Hi, they are used, but remember the flowers will never reduce in size, so you'll either want quite a large tree to look proportional, or if you have a small one, it would look best with only a couple of branches, a fat lower trunk tapering quickly to the apex, and only 1-2 flowers allowed to bloom. However, you're referring to a Rose of Sharon variety (outdoors) I think, but have not given your climate zone, and a tree that needs cold dormancy in winter would not do well indoors, though the 'regular' tropical hibiscus would not survive outdoors depending on where you live, so you may have to choose your growing place and stick to it, rather than have some outside and some in. Of course it will need lots of sun and water, but beyond that it's hard to say not knowing more.

Sorry about that, I live in north florida, hibiscus grow very well here all year round. and I am referring to a tropical hibiscus.

Hibiscus can work pretty well for bonsai, if as was said by another poster, you're ok with a larger bonsai.
I've got a very old Hibiscus bonsai, taken at one point from a 12' tree from a greenhouse where I used to live. It's about 18" around the base now, about 24" tall, 30" wide, and is a variegated leaf variety. I've had this for about 5 years now, and it's really getting pretty nice looking finally. It was tossed in the garbage due to some kind of issue causing it to drop leaves and look terrible. Like I said, it was 10-12' tall in the greenhouse and they just chopped it to the point that it would fit in the garbage. I defoliated it, sprayed it down with insecticidal soap, and later a fungicide, and left it alone for a couple months. Watered occasionally, and kept it protected. It did finally come back and has really been a good plant to work with after that. I'll get a picture posted soon.

Sounds incredible! Hurry back.

Need...pics...of..12yo............tree....serious dude come back i have a 4ft tall braided one from an aunt, gonna see what i cando