I can't give any real advice but I was treatment resistant as well. Tried practically anything that's ever used for bipolar mania to no avail and was rapid cycling and spent lots of time locked up. I lost all hope and thought I'd spend the rest of my life out of control and going in and out of hospitals. Until I went to an IOP where the pdoc there gave me clozapine. It works very well and is extremely effective. However, if you're prone to weight gain from antipsychotics I'd stay away from it as I find it is the worst of all the antipsychotics in that aspect. ECT has also been recommended for me and I have decided I'll give it a shot should I relapse.
I hope whatever you decide goes well for you.