The Agfa/Gaevart operation in Belgium coats b/w paper and color paper. It is in long rolls, and intended for printing of images taken with the various aerial photography films they also make. Here is the description straight from their website:

:Rapitone P1-P2: Photographic continuous tone papers in 4 gradations and 2 surfaces, used for making enlargements, contact copies and mosaics. Their gradations are adapted for good continuous tone rendering.

:Rapitone M2: Photographic black-and-white semi-matt paper with variable contrast through the use of colored filters. The paper has a gradual variation in gradation from extra low to very high contrast by using black-and-wnite enlargers with multi-contrast filters or enlarges equipped with la colorhead or filter head for multi-contrast paper.

and their color paper:

:Rapitone C1-C2 Aerial Papers: professional enlarging materials with a polyethylene resin-coated base, designed for the production of prints from color aerial negatives. Camera, internegative and copy films can be used as negatives. :Rapitone C1 has a glossy surface and C2 has a semi-matt surface.

So, there you have it...I wouldnt be a bit surprised if some relabelers already sell this stuff cut into sheets.

Ah, it is interesting isn't it, and back on topic, at last! Horray!!