I have recently seen some prints with split tones I would like to emulate. I queried the photographer, who said she partially bleaches the prints, on warm Forte paper, typically using selective bleaching with ferricyanide, then tones in selenium. The bleached areas of the print are a striking blue color after toning. I haven't tried it myself, but it's on my list.

Ilford Multigrade, as Les has intimated, is probably the worst paper on the market to try to tone (excellent in other ways, though).

I have a couple of articles on my site that might interest you: Double Toning Prints at http://unblinkingeye.com/Articles/Double/double.html, and Tips & Tricks for Blue Toning at http://unblinkingeye.com/Articles/Blue/blue.html.