I live in an apartment and use a 3000W ONEAC isolation transformer. I also have a Tice A/V Solo, but it's not a good idea to plug my amp to it.
You can get a *big* isolation transformer in eBay, but it is going to be 220V in for what you want it...
Sedond is using two VE unlimiters and is happy with them. I would try good power cords (whatever design, no debates here...) and also try a Highwire Wirewrap. For $25 it's worth a try--I have one to help my power amp and it smoothens sound by removing RF grunge.
Going to parallel filtration is also a good idea--as well as getting some surplus isolation transformers for your digital gear.