The 4824 only has 20MHz bandwidth, which is what I was referring to when I said "in this class". We got a 6404D, which has 500MHz bandwidth. This fulfills our primary goal with the purchase, and my current investigation focuses on trying to see if we can get more out of the investment.
The specific case is 4-bit SDIO running at 200MHz. Obviously some information will be lost as we only have 4 channels available, but since you can get 95% of the information from 3 channels (CLK, CMD and D1/IRQ), this is not a big loss. It just means that the data cannot be decoded, but since debug that involves data normally comes at higher levels in the stack, this is not critical.
Anything that can get us closer to the 1-bit streaming mode on 3-4 channels with as high sample rate as possible will be helpful.