My mind has been focusing on the medium range SAM, something in generally the same engagement envelope as the SA-11/17, Aster or early version of Patriot/S-300.
I'm still favouring IIR/AR seekers over the cheaper SARH/CI (command intercept) types, so this is like Aster or L-AMRAAM. The missile would be ramjet powered.
Such a missile would have to be about 4.5m long (slightly bigger than the PL-12, but smaller than the SA-17). See rough comparison below, my SAM being the bottom one below AA-10 Alamo and SA-11/17:
The AR seeker would be straight off the PL-12, and IIR seeker a new type (PL-8 is too old). As a contingency the missiles could engage using datalinked CI, but in the normal operation the missile would be launched under CI and then lock on after launch. The CI would be one-way, the missile would not send any data back, instead relying on its own computer to intercept.
I'm still keen on the VL pallet idea, but for mobile units advancing with troops an on-board targeting radar (with secondary search capability) and the ability to fire and move is vital, as is high mobility. So a tracked vehicle, although more expensive, would be worth it.
Because the missile is 4.5m long, VL is not viable. Plus the missile is hot launched which would add another complication in a layout like the SA-15. So slant launch is needed, and the layout ends up looking a lot like the SA-11/17 family, but with 6 boxed missiles and a phased array radar.