i wouldnt have a problem with some one putting these guys on the table and saying they "count as" cold one cavalry.
Were you inquiring as to the possibility of mounting the riders on the new cold one models from the saurus cav? If so, I don't think you will have any trouble doing that. The models are metal so you can probably just gently bend their legs to fit the newer cold one models. Post some pics when you have them put together!
If you already have the saurus cold ones then I wouldn't worry about it, but to be honest, I think the dark elf ones are the coolest to boot!
The only thing wrong I see with this is that they are so damn hard to find and you got your hands on them before me! (shakes fist)
i happen to have both minis, and yes, it would actually work (with some GS). the scale is not too far off imo, though these cold one are a bit smaller than the current plastic monstrosities.
As long as you use some green stuff as Lord Tsunami mentioned, you should be able to fit the new rider models on top of them without too much hassle. Hicks: I think I got 9 or 10 of these still in their wrapping and another 6 or so assembled, was one of my last purchases back in the days that I never got assembled before I stopped playing. I wont use them myself as Im like the look of the dark elf cold ones better myself so Ill do a conversion with those. If your still looking for these old models, drop me an PM, depending on your location we might be able to work something out.