For cambered plane blades I usually use a similar technique to straight edged blades. I got fed up with honing guides a while ago and found that if you ground the primary bevel fairly accurately, and on a rough stone shape the bevel to exactly how you want it (eg. straight with a honing guide, or cambered), when you resharpen you can just use your hand to guide the blade for a long time until you regrind the bevel.
You could go about it a few ways, such as with a Veritas roller as mentioned above, you could try find something called 'slip stones' which are like waterstones but are concave to allow you to sharpen tools with curved blades, or you could try do it freehand. I prefer to use the freehand method, after flattening the back of the blade I gently sharpen the blade by moving the area of the curve that's sharpened every few strokes from left to right until I'm happy that it's sharp all across the edge. Unless you're using very coarse stones, it'd take you a long time to wear the blade camber into an uneven shape, and if you end up using waterstones that long anyway you're using them wrong, waterstones should usually only require about 30 seconds of use for each grit at the most.