While the process is a bit of a pain in the butt to set up manually, fake duotone/tritone/quadtone images can be created using a "monochroming" layer¹ and a Gradient Map adjustment layer set to Color blend mode.

If you are using a Smart Object as your original image, though, you can create a conversion-and-preview template image that will speed up the process tremendously. Adobe guru Julianne Kost provides both the method and a template (using the CS6 gradient presets, but adaptable to other versions) on her Adobe blog. There is also a video tutorial available.

Setting up custom gradients will be a bit of a pain, but once they're done they're done, and you can use the templating technique to choose the best match for your image quickly. It won't be quite as handy as a good B&W conversion plugin with presets (like Nik Siver Efex Pro or Topaz Black & White Effects), but it'll take a lot of work out of future conversions.

¹ For the monochrome conversion layer, I'd suggest using a Curves adjustment layer rather than the more obvious Hue/Saturation; it will produce less tone shifting, especially when combined with contrast adjustment layers. Create a Curves layer, and drag the black point to the top. That will make the whole image white. Then set the layer blend mode to Saturation.