If you are looking for a quality photographic ink jet paper that will work for both Canon and Epson printers, you can look at some of the companies that have been making paper far longer than either of those two: Hahnemühle , Ilford, Museo Fine Art, Moab (Legion) Paper, etc.

Can't guarantee that the price will be much cheaper (may be more expensive, depending on the specific type of paper you select), however at lest those brands I've listed usually have ICC profiled for both brands of printers, and several models for each brand. You listed several key factors of a high quality print, such as accurate color reproduction, high sharpness, good density for a trained eye. Its tough to find a paper that offers a high level of those things and is also cheap.

Canon's fine art papers are actually made by Hahnemühle , and they may actually be cheaper than buying the same stuff from Hahnemühle direct. You might want to look at the HARMAN papers by Hahnemühle , as they may be cheaper (joint project between the founder of Ilford and Hahnemühle .) Ilford is renown for its papers, particularly its true photographic (exposed by light) papers, however they also have a good selection of quality ink jet papers. They might be cheaper than Hahnemühle , although possibly not quite as high quality.